A) Sub g(x) and h(x) into the equation:
x^2 + 3x - 40 - (-x -3)
= x^2 + 3x - 40 +x + 3
= x^2 + 4x - 37
Find x:
x= 4.40 and x= -8.40
b) Sub f(x) and g(x) into the equation:
(x^2 - 64) / (x^2 + 3x -40)
= ((x+8) x (x-8)) / ((x+8) x (x-5))
= (x - 8) / (x-5)
Find x:
x= 8 and x = 5
How to get those number:
(x^2 - 64) = x^2 - 8^2 = (x-8) x (x+8)
( x^2 + 3x - 40) = (x^2 + +8x - 5x - 40) = x( x + 8) - 5( x + 8) = (x-5) x (x+8)
Try to do c and d :)
Answer:
Part 1) 
Part 2) 
Part 3) 
Step-by-step explanation:
see the attached figure with letters to better understand the problem
step 1
In the right triangle ABC
we know that
The triangle ABC is a 
so
Is an isosceles right triangle
The legs are equal
therefore
AC=AB

step 2
Find the length side BC
Applying the Pythagorean Theorem]



step 3
Find the value of y
In the right triangle BCD
----> by SOH (opposite side divided by the hypotenuse)

Remember that

so

step 4
Find the value of z
In the right triangle BCD
----> by CAH (adjacent side divided by the hypotenuse)

Remember that

so

Well they are not in length