1:x^2-4=0,
(x-2)(x+2)=0
x=2或x=-2
2:x^2-2√3x+3=0,
(x-√3)^2=0
x=√3
3:(x-7)(2x+1)+7=0
2x^2-13x-7+7=0
2x^2-13x=0
x(2x-13)=0
x=0或x=13/2
x^2-4=0
(x-2)(x+2)=0
x=2或x=-2
x^2-2根号3x+3=0
(x-√3)²=0
x-√3=0
x=√3
(x-7)(2x+1)+7=0
2x²-13x-7+7=0
2x²-13x=0
x(2x-13)=0
x=0或x=13/2