Question

3х^2-12=0
х^2-3х=0
-7х^2=0
7х+3=2х^2+3х+3
х^2-4х=4=0

Answer 1

Ну в общем: 
3x^2-12=0
x^2=12/3
x^2=4
x1=+2
x2=-2