Hello from MrBillDoesMath!
Answer:
x = 50
Discussion:
(4x +5) ( 2x - 2) = 8x^2 - 8x + 10x - 10
= 8x^2 + 2x - 10 (A)
(16x^8)/(2x^6) + 90 = 8x^2 + 90 (B)
Setting (A) = (B) gives
8x^2 + 2x - 10 = 8x^2 + 90
Subtract 8x^2 from both sides:
2x - 10 = 90
Add 10 to both sides:
2x = 90 + 10 = 100
Divide both sides by 2:
x = 100/2 = 50
Thank you,
MrB