(x+8)÷3=6.5
(X+8)=6.5乘以3
X=19.5-8 X=11.5
(x+4.5)×4=20
(x+4.5)=20除以4
(x+4.5)=5 X=5-4.5 X=0.5
(x+1.5)×5=17.5
(x+1.5)=17.5除以5
(x+1.5)=3.5 X=3.5-1.5 X=2