The answer is C.
You need you use Pythagoras theorem 2 times to have 2 equations with the same sides i.e. for example a2 + b2 = 81 and a2 - b2 = 9.
You can do it as you have different triangles but with the same sides.
A. 18+2 = 20 abs 18-2= 17
The value of f(5) is 
Step-by-step explanation:
The function is 
To find
substitute
in 

Multiplying the terms, we get,

Adding the terms, we get,

Thus, the value of
is 
Answer:
x = 4
Step-by-step explanation:
we know that 72 and (2x + 10) add up to 90
90-72 = 18
(2x + 10) = 18
2x = 8
x = 4
8x-4 and 4(2x-1)
4(2x-1) the four needs to be distributed in the parentheses.
4*2x=8x
4*(-1)=(-4)
8x-4=8x-4