Can you solve this tricky indices and exponents question?
X³⁰⁰⁰ − X²⁰⁰⁰ = 48
At first glance, this mathematical problem looks extremely difficult because of its unusually large powers. But can you find a clever mathematical approach to solve it?
In this video, we challenge your mathematical thinking with an interesting indices question that tests your understanding of powers, exponents and algebra.
Watch carefully, try solving it yourself before checking the solution, and let us know your answer in the comment section!
Whether you're preparing for examinations, improving your algebra skills or simply love challenging mathematics problems, this challenge is for you.
This looks like an impossible equation, but it's very, very possible.
Welcome back to my channel.
So today we are asked to find the values of x.
Are you ready?
Now let's go.
The first thing we need to do is this.
You can see there's a connection between 3,000 and 2,000.
And that is because they share 1,000 as a common factor.
So let's bring that out and see how this looks like.
So 3,000 is the same thing as 1,000 multiplied by 3.
Also, 2,000 is the same thing
as 1,000 multiplied by 2.
Therefore, we can rewrite this equation
as x to the power of 1,000 multiplied by 3
minus x to the power of 1,000 multiplied by 2.
And this is equal to 48.
Now, let's bring this to this side.
We will have
x raised to the power of 1000 multiplied by 3 minus x to
the power of 1000 multiplied by 2 minus 48 is equal to 0.
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Recall.
a to the power of m times n is the same thing
as a to the power of m raised to the power of n okay
and also equal to a to the power of n raised to the power of m
so these two can be interchanged
therefore we can write this as x to the power
of one thousand raised to the power of three
minus x to the power of one thousand raised to the power of two
Minus 48 is equal to 0.
Now, you can see x equal to 1000, that's a big number.
So, we can actually simplify.
So, we can say let x equal
to 1000 be equal to a.
And if that is the case,
that means this equation automatically becomes a to the power of 3
minus a to the power of 2 minus 48 is equal to 0.
Alright, now, because I want to factorize this,
let's do it this way then.
a to the power of 3 minus a to the power of 2,
I need a cube from here and a square as well from here.
And the available cubes
and squares is going to be negative 64 and plus 16, right?
Because this plus this will give me negative 48, is equal to 0.
Now, 64 is 4 to the power of 3,
so it's a cube, and 16 is 4 to the power of 2.
So, we can write this as a to the power of 3 minus 4
to the power of 3 minus 64 is 4 to the power of 3,
and plus 16 is 4 squared is equal to 0.
Now, let's collect like terms.
So we have a to the power of 3
minus 4 to the power of 3.
Then we have minus a squared
and plus 4 squared is equal to 0.
Now, recall, I want to put this in brackets.
So I can write this as a to the power of 3 minus 4 to the power of 3.
Then minus.
This becomes a squared.
But this becomes minus 4 squared is equal to 0
because minus minus will give me plus.
So now 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 plus ab plus b squared.
And also a squared minus b squared is equal
to a plus b multiplied by a minus b.
So I'm going to expand this equation now.
Using these two algebra identities.
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If not, I think this is the right time
to do that, okay?
Alright, now we have...
This will now be written in this form as
a minus 4 multiplied
by a squared plus 4a plus 4 squared, right?
That is it for this one.
Then minus, that means I need to arrange this side
as well, okay? So minus, for this, we are going
to have a plus 4 multiplied
by a minus 4 is equal to 0.
Now, I want us to look closely because you are going
to notice that we have a minus 4 here and a minus 4 here.
So, we can actually factorize that out.
So, if we do that, we have a minus 4, open bracket, this one.
So we're going to have a squared plus 4a plus 4 squared and then
we are going to have minus bracket a plus
4 for this one and this will be equal to 0.
So if we continue, we are going
to have a minus 4 open bracket
a squared plus 4a plus 4 squared.
Now this minus, we open this bracket as minus a and minus 4.
This is equal to zero. Now let me come to this side.
So moving forward we have a minus four
bracket a squared plus 4a minus 4
a is plus 3a and 4 squared is sixteen.
Sixteen minus
four is twelve so we have plus twelve is zero.
Now from here you can see that a minus four is zero
And a squared plus 3a plus twelve is also zero
Remember, we are not looking for a,
we are actually looking for the values of x, right?
But from here, if this crosses, we have that a is equal to 4.
Then from here, let's go ahead and solve.
From here, we are going to use
the quadratic equation formula that says that
a will be equal to minus b okay let's use x okay x
is equal to minus b plus or minus
square root of b squared minus 4ac everything divided
by 2a now in this case a is what
1 b is 3 and c is 12. i'm talking about
a b c of this particular formula
So, we can now solve this x. Remember,
this x is representing what we are looking for
here, which is this x. So, this x now will
be equal to minus 3 plus or minus square root
of 3 squared minus 4 multiplied by 1 multiplied by,
our c is 12, divided by 2 multiplied by
So our x will be...
Minus 3, plus or minus.
The square root of 9 minus 48 divided by 2.
Now, from our discriminant,
we are going to notice that we are going to have a negative here,
which means that there is no real root, right?
No real roots.
So we are going to what?
We are going to discard this one.
We are going to leave this one.
So we are concentrating on a equals 4 right now.
So, we are going to find the values of our x using a equals 4.
So, but a is equal to 4.
And recall that we have that x
to the power of 1,000 is equal to a, right?
Therefore, we can say x to the power of 1,000 is equal to 4.
Now, let's raise both sides of this equation by 1 over 1,000.
So we have x to the power of 1,000 raised to the power of 1 over 1,000
is equal to 4 raised to the power of 1 over 1,000.
Now on this and this we go, we have x is equal
to 4 raised to the power of 1 over 1,000.
But we can still express 4 as 2 to the power of 2, right?
So we have x equals 2 to the power
of 2 raised to the power of 1 over 1,000.
Which we can divide this and this to have 500, okay?
So finally, we can now say
that x is equal to 2
to the power of 1 over 500.
Thank you so much for watching and see you in my next video.
Bye.