Can you find the value of x in this challenging algebra question?
At first glance, this equation might look complicated, but understanding the right mathematical approach makes all the difference.
In this lesson, we explore a challenging algebraic equation involving indices, algebraic fractions, and simplification. I'll take you through the solution step by step to help you understand how to approach similar mathematics problems.
This lesson is useful for students preparing for mathematics examinations, improving their algebra skills, or simply looking for interesting maths challenges.
Before watching the full explanation, take a moment to solve the question yourself.
What value of x did you get? Share your answer in the comments!
Subscribe to JJ Online Maths Class for more interesting mathematics lessons, algebra tutorials, examination questions, and challenging maths problems.
Remember, understanding mathematics is more important than memorising formulas.
looks impossible, but with the right approach we get
The answer: Welcome back to my channel, first.
This thing is over one, and we can cross multiply.
And if we do that, we will have x equal to 5.
x plus 1 is equal to 1211 multiplied by x
squared plus x plus 1. Now let's transfer this
This to this side and this to this side as well.
so we are going to have x to the power of five
is equal to one thousand we are opening this bracket
now one thousand two hundred and eleven x squared
then this time this will give us plus one thousand
two hundred and eleven x plus this time
This is one thousand two hundred and eleven.
Now I'm bringing this to this side.
so we are going to have minus x minus one
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so here we have x to the power five is equal
to one two one one x squared right one one x squared
one thousand two hundred plus one
and eleven x minus x is one thousand two hundred and ten x
one thousand two hundred plus one
and eleven minus one is one thousand two hundred and ten
Now I want you to look closely.
Because one thing about math is being so observant—now look at this.
We have 1210, 1210. Is there anything we can do?
Do this to get 1210, yes, we can actually rewrite this.
Let's decode 5 equal
to 1,210x squared plus x squared, right?
Then plus 1,210x.
plus one thousand two hundred and ten now looking
At this, we have this; we go to the other side, so we
x to the power of five minus x to the power of two
is equal to one thousand two hundred and ten
x squared plus one thousand two hundred
and ten x plus one thousand two hundred and ten
We can factor out x squared from this side.
So we have...
x squared brackets when this is divided
by this we are left with x cubed so
we have x to the power of three minus
When this is divided by this, we have one, all right, minus one.
is equal to one thousand two hundred
and ten x squared plus one thousand two hundred and ten x
one thousand two hundred and ten
Okay, minus x, okay. If we solve for that.
Remember that a to the power of 3 minus b
to the power of 3 is equal to a minus b multiplied
by a squared minus ab plus ab plus b squared, okay?
So, you can actually express x to the power
of 3 minus 1 to the power of 3, right?
Because 1 to the power of 3 is still 1.
So, you can actually express this as x to the power of 3 in parentheses,
x cubed
minus one to the power three for the left hand side
is equal to 1210 times x squared plus
1210x plus 1210
then we expand in this form
So we'll have, let me extend
My hand a bit, all right.
so we have x to the power of two brackets
and this will give us x minus one multiplied by
x squared plus 1 times x, which is still x plus 1 squared
Which one is equal to this, right?
1210x² + 1210x + 1210
Now it's high time, let's expand.
this and factorize this side
So we have
So 2 9 2 2 1 2 2 1 2 9 2 2 2 2 2 2 2 2 2 2 2 2 3 2 2 0
x squared times x is x to the power three
and x squared times minus 1 is minus x squared
(x² + x + 1)
is equal to
Now we are going to factorize 1210, okay.
so we have 1210 (sorry, this concept)
This will be x squared plus this times this, and this x will remain.
Plus this into this one, are you seeing anything we have?
this and we have that amazing
Right now, let's transfer this to this side.
so that we can factor out this common factor, we have x
x cubed minus x squared brackets x
x squared plus x plus one minus one thousand two
210, open bracket, this, right?
x squared
x plus 1
is equal to zero; now we can factorize this, so if we
do that we have x squared plus x plus one
open brackets so this will remain
when this is divided by this, we have this remainder, x to
the power of three minus x squared then
When the entirety of this is divided by this, we obtain this.
Minus 1210 is equal to 0
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video all right okay
so from here we can see that we can say that x squared
plus x plus one equals zero and
x cubed minus x squared minus 1210
and 10 is also 0.
Now, for this side, we can solve for x,
If we should use the quadratic formula, right?
If we use the quadratic formula,
Our a is 1, our b is 1 as well, and our c is 1, okay?
So, using the quadratic
equation formula that states that x is equal to
The quadratic equation formula states that x
is equal to minus b plus or minus square root
negative b plus or minus the square root of b squared minus 4ac, all divided by 2a.
So if we substitute, we have x is minus 1 plus
or minus the square root of
1 squared minus 4 multiplied by
Remember, our a is also 1, our c is also 1.
Everything divided by 2, multiplied by a, which is 1.
So we have that x is equal to minus 1 plus
or minus the square root of 1 squared is 1.
4 times 1 times 1 is still 4.
everything divided by 2, remember
that we will still solve this and we are going
to get more values from here, so watch the end
and see how we obtained additional values from this side
Now let's continue, so I'm going to copy this out.
because we are solving it next x to the power
3 minus x squared minus 1210 equals 0
We're almost there, okay? So now we have our x to be
equal to minus one plus or minus square root of
negative three divided by two this implies
that x equals minus one plus or minus square root of
three i divided by two, that is because minus three
is the same thing as three times negative one
and the square root of minus one is i
Alright, yes, the square root of minus one is i.
and that's where this i comes from, root three
and the square root of minus one, so from here you can see
that we have obtained the first and second values of our x
One and two—that's one. Now let's continue.
with the other roots that with the other
the equation we have now
The other equation I copied down says x equals three minus x squared.
minus one thousand two hundred and twenty-four equals zero
then we have x to the power of three minus eleven x squared plus
ten x squared minus one thousand two hundred and ten is zero
So if we factorize this here, we have x squared remaining, right?
or as a common factor, then x cubed divided by x squared
We have x minus eleven x squared divided by x squared, which is still eleven.
plus here we have 10 then x squared divided by 10 we
x squared then minus one two one zero
divided by this we have minus one times two plus one is equal to zero
so here we have x squared brackets x minus 11 plus
10 times the square. Now look at these two brackets; they are similar.
because 121 is the same thing as
11 squared, we already have 11 here
so we have minus 11 squared is here now remember that a squared
minus b squared is equal to a minus b multiplied
a plus b, therefore we can now write this as
x squared, brackets, x minus 11
x plus 10 into x minus 11 multiplied by x plus 11 equals zero
so if you look at this and this
They now have x minus 11 in common.
and we are factoring that out, so we have x minus 11 into
For this side, x squared will remain; for this side, 10.
into this will remain 10 brackets x plus 11
Equals 0.
So, we have x minus 11
x squared plus 10 times x
Is 10x plus 10 times 11 equal to 110 equal to 0?
Are you still there?
If you are, thank you very much.
❤️
For me, that would show that you actually watched up to this point, okay?
so let's confuse those who
Didn't watch to this point, just one heart emoji. Thank you. Now looking.
At this, we have from here
that x minus 11 equals 0
x squared plus 10x plus 110
equals 0. If we solve for that
I want to make sure this is clear.
now if we solve for that, we can see
that x equals 11, so this becomes the third value
of our X now for this we are going to solve using
the quadratic formula as well
so where a is 1, b is 10, that is the coefficient of x
and c is a constant, so if you use the quadratic
quadratic formula
x will be minus 10 plus or minus the square root
10 squared minus 4 multiplied by 1
by 1 1 0 right 480 all over 2 multiplied by 1.
So, if we continue, we have x equals minus 10.
plus or minus square root of 100 minus 440
everything divided
by two, okay, now moving
forward we have x equals
minus 10 plus or minus
the square root of minus 340 divided by two, can we
Factorize this 340. Let's check if we can reduce it.
to a simpler form so we go through this 170 times
So we go into this 85 times and
Okay, five, we go into this one, one, okay. I think we
We've gotten what we wanted: four and eighty-five.
Four is a perfect square.
so we can now write x to be minus 10 plus or minus square root of
four times 85 times negative one
because of the negative sign, now everything
divided by two, so x equals negative 10 plus
or minus now the square root of 4 is 2
We have 2 root 85 and square root
of negative 1 is i divided by 2, so our x
which will be the fourth
and the fifth value will be 2; we go into this minus 5
plus or minus, we go into this one, so we are left with this
square root of 85 I thank you so much for watching
See you in my next video, bye