Question

Найдите корни уравниения 2x-9=(x-3)(x+3)

Answer 1

2x-9=(x-3)(x+3)
2x-9-(x^2-9)=0
2x-9-x^2+9=0
2x-x^2=0

D=2^2-4*(-1)*0=4

x1=(2-2)/(2*(-1))=-0/2=0
x2=(-2-2)/(2*(-1))=4/2=2