1、解方程。 2x-16=5.6 (x+6.9)÷4=2.5 2x-16+16=5.6 +16 (x+6.9)÷4×4=2.5×4 2x=21.6 x+6.9=10 X=10.8 x+6.9-6.9=10-6.9 x=3.1 3.2x+1.5×2=12.6 5(x-2.5) =5.5 3.2x+3=12.6 5(x-2.5)÷5 =5.5÷5 3.2x+3-3=12.6-3 x-2.5=1.1 3.2x=9.6 x-2.5+2.5=1.1+2.5 3.2x÷3.2=9.6÷3.2 X=3.6 x=3 (2x-4.6)÷6=1.8 (2x-4.6)÷6×6=1.8×6 2x-4.6 =10.8 2x-4.6+4.6 =10.8+4.6 2x =10.8+4.6 2x=15.4 2x÷2=15.4÷2 x=7.7