解方程:(1)x²-2x-1=0 (2)y²-6y+6=0 (3)3x²-6x+1=0 (
2个回答

(1)x²-2x-1=0

x²-2x+1=2

(x-1)²=2

x=1+√2 x=1-√2

(2)y²-6y+6=0

y²-6y+9=3

(y-3)²=3

y=3+√3 y=3-√3

(3)3x²-6x+1=0

x²-2x=-1/3

x²-2x+1=2/3

(x-1)²=6/9

x=1+√6/3 x=1-√6/3

(4)5x²=6x+8

x²-6x/5=8/5

x²-6x/5+9/25=49/25

(x-3/5)²=49/25

x-3/5=7/5 x-3/5=-7/5

x=2 x=-4/5