4-x=2(-0.5x²+2.5x-2)

4-x=2(-0.5x²+2.5x-2)
4-x=2(-0.5x²+2.5x-2)

4-x=2(-0.5x²+2.5x-2)
解
4-x=2(-0.5x²+2.5x-2)
4-x=-x²+5x-4
x²-6x+8=0
(x-4)(x-2)=0
∴x=4或x=2

得：X=2或4

4-x=2(-0.5x²+2.5x-2)
4-x=-(x²-5x+4)
x²+4x=0
x(x+2)=0
x1=-2
x2=0