0.8X*(0.5+0.4)=4.32
0.72x=4.32
x=6
x-2分x+1=2+2分x+1
(x+1)/(x-2)=2+(x+1)/2
2x+2=4(x-2)+(x+1)(x-2)
x^2-x-2+4x-8-2x-2=0
x^2+x-12=0
(x+4)(x-3)=0
x=-4或3