Answer: x=-3 or x=-5
(2x^2 + 8x -10)\( 2x^2 + 14x + 20)=4
2x^2 + 8x -10=( 2x^2 + 14x + 20)×4
2x^2 + 8x -10=8x^2 + 56x + 80
8x^2 + 56x + 80-(2x^2 + 8x -10)=0
8x^2 + 56x + 80-2x^2 - 8x +10=0
6x^2 +48x +90=0
6(x^2 +8x +15)=0
x^2 +8x +15=0
(x+3)(x+5)=0
(x+3)=0 or (x+5)=0
x=-3 or x=-5
