(1) 0.7(3x-3.7)-4=-1.3(3x-3.7) (2) 60%(y-1)=0.1+34%(y+1) (3) (0.2分之0.3+0.2x)+0.5x=0.75

问题描述:

(1) 0.7(3x-3.7)-4=-1.3(3x-3.7) (2) 60%(y-1)=0.1+34%(y+1) (3) (0.2分之0.3+0.2x)+0.5x=0.75

(1) 0.7(3x-3.7)-4=-1.3(3x-3.7)
0.7(3x-3.7)+1.3(3x-3.7)=4
2(3x-3.7)=4
3x-3.7=2
3x=5.7
x=1.9
(2) 60%(y-1)=0.1+34%(y+1)
60(y-1)=10+34(y+1)
60y-60=10+34y+34
26y=104
y=4
(3) (0.2分之0.3+0.2x)+0.5x=0.75
(3+2x)/2+x/2=3/4
2(3+2x)+2x=3
6+4x+2x=3
6x=-3
x=-1/2