(3-y)²+y²=9
2y平方-6y =0
y(y-3)=0
y1=0
y2=3
(2x-1)²-5(2x-1)-6=0
(2x-1-6)(2x-1+1)=0
2x(2x-7)=0
x1=0
x2=3.5