Algebra simplification|No calculator.

JJ ONLINE MATHS CLASS
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Video Summary
AI GeneratedThis video provides a step-by-step mathematical tutorial on how to simplify a square root expression involving the sum of three cubed numbers: $30^3$, $40^3$, and $50^3$. The instructor demonstrates two different algebraic methods to arrive at the final simplified answer of $120\\sqrt{15}$.
First, let us simplify what we have here.
I am going to solve this using two methods.
So this particular one is the first method.
Now, in the first method, we are going to
What is this 30 sentences as?
10 times 3, right?
raised to the power of 3
plus this sentence as
4 multiplied by 10 equals 40.
raised to the power of 3
plus this sentence as
5 times 10
raised to the power of 3
What is it equal to?
Now, we factorize.
But before that, let's open this bracket.
According to the law of indices,
a multiplied by n
raised to the power of b
is equal to a to the power of b
multiplied by n to the power of b.
So we are going to use this
or we are going to express this in this form.
So, if we do that,
then we have
10 to the power of 3
multiplied by 3 to the power of 3
4 to the power of 3 plus 4
multiplied by 10 to the power of 3
5 to the power of 3 plus 5
multiplied by 10 to the power of 3
What is it equal to?
Now, let's go ahead and factorize.
Because when you look at this,
Notice that we have 10 to the power of 3.
10 to the power of 3 and 10 to the power of 3
So we are going to factorize it
To simplify this particular question.
So we do that right now.
We are going to have
10 to the power of 3.
We open our bracket.
When this is divided by 10 to the power of 3,
we have 3 to the power of 3
plus when this is divided by this,
we'll have 4 to the power of 3
plus when this is divided by this,
we'll have 5 to the power of 3.
Okay.
Now, this is equal to
square root of 10 to the power of 3
multiplied by
Remember that this is the first method.
That we have two methods, right?
We are going to use two methods to solve this.
What is 3 to the power of 3?
That is 3 times 3 times 3
And that's 27, right?
So we have 27 plus
What is 4 to the power of 3?
Four times four is sixteen.
16 times 4 should be 64, right?
So we have 64
Five to the power of three is 125.
Okay.
Now, let's move to this side.
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Thank you so much.
So this is where we are.
Let me copy it out.
The square root of
10 to the power of 3
ctypes MATCH 27
64 plus 125.
Perfect.
Now, this is equal to
square root of 10 to the power of 3
multiplied by
Now let's add this.
If we add, we have
125, 64, 27.
Now, 5 plus this makes 9.
And 9 plus 7 is 16.
We carry 1.
This will give us 10
Plus 1 is 11.
Then we add 1 here.
We have 216.
216
So this is the square root of 10 to the power of 3.
multiplied by 216.
Now, this is equal to
The square root of what?
10 to the power of 3
Now, 216 is 6 to the power of 3, right?
multiplied by 6 to the power of 3.
Now, when you have the same power
just as we did here,
We are going to bring this into the bracket.
And we're going to bring the 3 outside.
So if we do that, we will have
10 times 6
raised to the power of what? 3.
Now, this is equal to
The square root of 16 raised to the power of 3.
Now, we can express this as what?
We can express this as
square root of 16 squared
multiplied by 16 to the power of 1.
Using the law of exponents,
we have that a to the power of m
multiplied by a to the power of n
is equal to a to the power of m plus n.
That is why we can express this as that.
Now, let's continue.
So, we can now open this bracket
or we can distribute this square root sign
For both of them.
So, we have the square root of 16 squared.
multiplied by the square root of 16
Alright, let's continue from here.
If we do that, then we have
Now, the square root of 16 squared
Will give us 16, right?
So, we have 16 here.
So, 16 multiplied by the square root of 16, right?
Square root of 16.
Now, this is equal to 16 multiplied by
Now, 16 is the same as 4 times 15.
4 multiplied by 15 equals 60.
Now, this is equal to 16 multiplied by
So, this is the same thing as the square root of 4.
multiplied by the square root of 15, right?
Now, this is 16 multiplied by
The square root of 4 will give us 2.
multiplied by the square root of 15.
So, this is equal to 120 root 15.
That concludes the first method.
Now, let's use the second method.
Now, let's move on to the second method.
That is method 2.
So, this is equal to the square root of
Now, 30 to the power of 3 simply means
30 plus 30 times 30
Sorry, 30 times 30 times 30
which will give you 3 times 3 times 3
I'll give you 27.
And we have three zeros, right?
1, 2, 3.
So, that means this is 27,000.
So, we have 27,000
plus, similarly, 40 times 40 times 40.
We are going to have three zeros.
Then, 4 to the power of 3, which is 64, right?
So, we have 64,000
Besides, here we are going to have three zeros.
And 5 to the power of 3 is 125.
So, 125,000.
Okay.
Then, we go ahead.
If you add this together,
What are you going to have?
We are going to have 216,000
because we have added something similar to it before.
Right?
Now, this is equal to the square root of 1,000.
multiplied by 216.
So, this is equal to
square root of 10 to the power of 3
multiplied by 6 to the power of 3
Now, if we continue, we have
What is the square root of this?
10 times 6
raised to the power of 3.
Okay.
So, this is equal to
cube root of 60
which is equal to
square root of 60 squared
multiplied by 60
which is equal to
square root of what?
Square root of 60 squared
multiplied by the square root of 60.
Okay.
So, we divide this.
We are left with
60 multiplied by
square root of 4 times 15
So, this is 60 multiplied by
This is 2 root 15, right?
And which will still give us the same answer
which is 120 root 15.
Thank you so much for watching.
Have a lovely day.
