Answer:
d) 
Step-by-step explanation:
b) 
This expression is not equivalent, as the original expression,
, has 9 multiplied to
instead of y. You can interchange values like this when it comes to addition, but not multiplication.
c) 
This expression is also not equivalent. After opening up the parentheses, it would again result in y being multiplied to
.

d) 
This expression is equivalent, as 9 and
are still being multiplied together and y is added to the product. We can actually rearrange this to look like the original expression:

I hope this helps!
2(a+bc)=2a+2bc
3.(ab-cb-ba+bc)= 3ab-3cb-3ba+3bc
Since the brackets and multiplication have a higher order than the rest.
Cb=Bc
Ab=ba
Ac=Ca
Because multiplication is commutative.
2a+2bc + cb +ab + ac -(3ab-3cb-3ba+3bc)
2a + 2bc + cb + ab + ac(+ -3ab - - 3cb - -3ba +-3bc)
2a + 2bc + cb + ab + ac -3ab + 3cb + 3ba -3bc
2a + (2bc-3bc +cb + 3cb ) + (ab -3ab + 3ba) + ac
=2a + 3cb + ba+ ac OR 2a +3bc + ab + ac
The Or is just a different way to write it.
Hope this helps
Answer:
9. 6k + 5 and 2k - 1.
10. 5√2 .
Step-by-step explanation:
9. Area = 12k^2 + 4k - 5
Factoring:
12k^2 - 6k + 10k - 5
= 6k(2k - 1) + 5(2k - 1)
= (6k + 5)(2k - 1)
So the required lengths are 6k + 5 and 2k - 1.
10. The ratio of a leg to the hypotenuse is 1: √2 so if the hypotenus = 10 the length of a leg is 10 / √2
= 10 √2 / 2
= 5√2 .