square both sides to get:
x^2-4x-5 = 4x^2 -40x + 100 re arrange terms to simplify
0 = 3x^2 - 36x +105 divide by 3 to simplify
0 = x^2 - 12x +35 factor to solve
0 = (x-7)(x-5) x thus equals 7 and 5
square both sides to get:
x^2-4x-5 = 4x^2 -40x + 100 re arrange terms to simplify
0 = 3x^2 - 36x +105 divide by 3 to simplify
0 = x^2 - 12x +35 factor to solve
0 = (x-7)(x-5) x thus equals 7 and 5