① 3(x-4)²=x²-16
3(x-4)²-(x+4)(x-4)=0
(x-4)(3x-12-x-4)=0
(x-4)(2x-16)=0
x1=4 x2=8
② (x-3)²-2(x-3)+1=0
(x-3-1)²=0
x1=x2=4