Answer:
D. log(9)
Step-by-step explanation:

Remember: 

Remember: 

Simplify...

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Answer:
1 A= pi 21^2
2 C=pi 21
3 A= pi 10.5^2
4 C= 2pi 10.5
Step-by-step explanation:
Solution:
iv) Given equation: 
Since we are given two variables, we need to split the original expression into two quadratic expressions as

Factoring x first:

= 
= 

Factoring y now:

= 
= ![-1[ y(y+1) + 1(y+1)]](https://tex.z-dn.net/?f=-1%5B%20y%28y%2B1%29%20%2B%201%28y%2B1%29%5D)
= ![-1 [(y+1)(y+1)]](https://tex.z-dn.net/?f=-1%20%5B%28y%2B1%29%28y%2B1%29%5D)
= 
Therefore, the original expression becomes

Percentage change = difference/original x 100
(9.00-7.50)/7.50 x 100 = 2.50/7.50 x 100
= 1/3 x 100
= 33.3% increase