1) (3-2)^2=48+(2-х)^2
2) (1+х)^2=(1-2х)^2
3) х^2+5х+42=х(2х+6)

148+(2-x)²=1(2-x)²=-47нет решения2(1+x)²-(1-2x)²=0(1+x-1+2x)(1+x+1-2x)=03x*(2-x)=0x=0  x=23x²+5x+42-2x²-6x=0-x²-x+42=0x²+x-42=0x1+x2=-1 U x1*x2=-42x1=-7 U x2=6