2) x²+4х-12=0
x²+4х +4 -16=0
(x+2)² - 4² =0
(x+2 -4) (x+2 +4) =0
(x-2)(x+6)=0
x-2=0 ; x1 =2
x+6=0; x2 =-6
4) х²-10х+16=0
х²-10х+25 -9=0
(x-5)² - 3² =0
(x-5 -3) (x-5 +3) =0
(x-8)(x-2) =0
x-8 =0 ; x1 =8
x-2 =0 ; x2 = 2
6) х²+8х-7=0
х²+8х+16 -23=0
(x+4)² -23 =0
(x+4 -√23) (x+4 +√23) =0
x+4 -√23 =0 ; x1 = -4 +√23
x+4 +√23 =0; x2 = -4 -√23
X в квадрате -10x +16=0
x^2-10x+25-9=0
(x-5)^2=9
!x-5!=3
x=8
x=2