1. 8.5x-2.5x=24.6 2. (x-1.8)/3=2.6 3. 2(x+1.7)=9.2 4. 2.4x-2x1.05=2.7（帮个忙挖,尽量解）

1.8.5x-2.5x=24.6
6x=24.6
x=4.1
2.(x-1.8)/3=2.6
x-1.8=7.8
x=9.6
3.2(x+1.7)=9.2
x+1.7=4.6
x=2.9
4.2.4x-2x1.05=2.7
2.4x=0.6
x=0.25