ANSWER
By simplifying the left hand side using the Pythagorean Identity.
EXPLANATION
The given identity is

Take the left hand side and simplify to get the right hand side.

Collect LCM for the denominators.

Recall the Pythagorean Identity.

This implies that:

We substitute this to get,


15. -2
16. A. The pool was originally empty
Answer:
49
Step-by-step explanation:
14x14 = 196
196/4 = 49
So if 6 out of 40 are incorrect, 40-6= 36 must be correct.
In order to gain percentage you do proportions.
36/40 = x/100.
Multiply 36 times 100 then divide by 40, which is 90.
The answer is 90%.
90% of the questions he got were correct.