1200/x-2-1200/x=30

问题描述:

1200/x-2-1200/x=30

1200/x-2-1200/x=30
40/x-2-40/x=1 两边乘x(x-2)
40x-40(x-2)=x*(x-2)
x²-2x=40x-40+80
x²-2x-80=0
(x-10)(x+8)=0
x1=10 x2=-8