x^2-4x-3=0
x^2-4x+4-7=0
(x-2)^2=7
x-2=根号7或-根号7
x=2+根号7或2-根号7
x²+8x-9=0
x^2+[9+(-1)]x+(-1)*9=0
(x-1)(x+9)=0
x1=1,x2=-9
x²-6x+4=0
x^2-6x+9-5=0
(x-3)^2=5
x-3=根号5或-根号5
x=3+根号5或3-根号5
x^2-4x-3=0
x^2-4x+4-7=0
(x-2)^2=7
x-2=根号7或-根号7
x=2+根号7或2-根号7
x²+8x-9=0
x^2+[9+(-1)]x+(-1)*9=0
(x-1)(x+9)=0
x1=1,x2=-9
x²-6x+4=0
x^2-6x+9-5=0
(x-3)^2=5
x-3=根号5或-根号5
x=3+根号5或3-根号5