<span>(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</span>
(tg67 – tg22)/(1 + tg67*tg22)=tg(67-22)=<span>tg45=1</span>
X^2+4x+4=x^2-8x+16
x^2+4x+4-x^2+8x-16=0
12x-12=0
12x=12
x=1