To re-phrase this: 50 is a certain percent of 90.
this can be written mathematically as 50=x%*90
let's divide both sides by 10:
5=x%*9
and divide both sides by 9:

which in decimals is approximately 0.56 (but not exactly).
so 0.56=x%
and the x then 56
so 50 is
approximately 56% of 90:
exactly 56%of 90 is 50.4
Divide both sides by 5^2 (which is 25). So p = (5^12)/25. I can't be bothered to plug in into a calculator but be my guest.
Answer:

Step-by-step explanation:

First, we expand the equation using the distributive rule:

Hence, 
Simplify: 
Add like terms:

Subtract 13 from both sides: 
Divide both sides by -8:

The answer would be C, sorry if I’m wrong
He made the first error in number 3