4(X+0.5)+X=17 X=3
4X-3(20-X)=6X-7(9-X) X=1/2
6+3分之X=(8-2X)÷2 X=-3/2
(X-3)÷2-(2X+1)除3=1 X=-17
(0.1X-0.2)÷0.02-(X+1)÷0.5=3 X=5