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# C2 questions watch

1. 2. Simplify these expressions:

b) x-2 ÷ x-3

d) (2x2 ÷ 4y3 )-2

On 2b I get

On 2d I don't understand any of it.. what am I missing out on? Answer is
4y6 / x4
2. For b), you can write this as (1/x2)/(1/x3) - multiplying both the numerator and the denominator by x3 gives you x /1 = x

For d), you flip the fraction and square it.
[(4y3)/(2x2)]2 = (16y6)/(4x4) = (4y6)/(x4)
3. (Original post by ckfeister)
2. Simplify these expressions:

b) x-2 ÷ x-3

d) (2x2 ÷ 4y3 )-2

On 2b I get
Note the rule that .

So here you're doing

n 2d I don't understand any of it.. what am I missing out on? Answer is
4y6 / x4
Again, same thing here:

Can you take it from here knowing that and ?
4. For 2b, the powers that x is raised to are both negatives. So x^-2/x^-3 becomes x^(-2--3) and since 2 negatives make a positive, it becomes x^(-2+3) which is x^1. And x^1 is obviously just x.

For 2d, the whole bracket is raised to the power of -2. When a number is raised to a negative power, it becomes an inverse. So you get 1/(2x^2/4y^3)^2. The whole bracket is now squared. 2x^2 squared is 4x^4, and 4y^3 squared is 16y^6 - you add the indices. So then you have 1/4x^4/16y^6. Since you're dividing by a fraction, the denominator is multiplied by the numerator. So you now have 1(16y^6)/4x^4 which is just 16y^6/4x^4. You can simplify this fraction by taking out 4, so then you're left with 4y^6/x^4
5. (Original post by Zacken)
Note the rule that .

So here you're doing

Again, same thing here:

Can you take it from here knowing that and ?
How did you get
? - this part
6. (Original post by ckfeister)
How did you get
? - this part
Standard GCSE fractions,
7. (Original post by Zacken)
Standard GCSE fractions,
Where on Earth did that x^3 come from?
8. (Original post by ckfeister)
Where on Earth did that x^3 come from?
Oh c'mon, you must remember that when you do things like adding fractions, you can multiply a fraction by 1.

So for example, to do you'd do .

This is the same thing here, we're doing .

If you don't like thinking of it like that, then what about .

Any help?
9. (Original post by ckfeister)
2. Simplify these expressions:

b) x-2 ÷ x-3

d) (2x2 ÷ 4y3 )-2

On 2b I get

On 2d I don't understand any of it.. what am I missing out on? Answer is
4y6 / x4

Sorry about the quality of the picture! :P Also, where I've added the indices - that was a mistake. It was meant to be multiplying

10. (Original post by Zacken)
Oh c'mon, you must remember that when you do things like adding fractions, you can multiply a fraction by 1.

So for example, to do you'd do .

This is the same thing here, we're doing .

If you don't like thinking of it like that, then what about .

Any help?
yes, thanks
11. (Original post by ckfeister)
yes, thanks
Cool.
12. (Original post by JustARandomer123)

Sorry about the quality of the picture! :P Also, where I've added the indices - that was a mistake. It was meant to be multiplying
perfection, simple enough for a baby to understand.. good.
13. (Original post by ckfeister)
perfection, simple enough for a baby to understand.. good.
14. (Original post by otah007)
\left(\frac{2x^2}{4y^3}\right)^{-2}=\frac{\left(2x^2\right)^{-2}}{\left(4y^3\right)^{-2}}=\frac{\left(4y^3\right)^{2}} {\left(2x^2\right)^{2}}=\frac{ \left( 2y^3 \right)^{2}}{\left(x^2\right)^{2 }}=\frac{4y^6}{x^4}
Fixed:
15. (Original post by Zacken)
Fixed:

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