Question

(2x-1)(2x+1)+x(x-10=2x(x+1)

Answer 1

(2x-1)(2x+1)+x(x-10)=2x(x+1)
(4x²-1)+x²-10x=2x²+2x
3x²-12x-1=0
D=(-12)²-4·3·(-1)=144+12=156=4·39
x₁=(12-2√39)/6=(6-√39)/3    или     х₂=(6+√39)/3