Question

(x+1.6)÷4.5=4.8解方程

解方程．
（x+1.5）×2=7
1.2×4-x=2.1
2.7x-1.6=38.9
x÷4.5=20．

Answer 1

①（x+1.5）×2=7
（x+1.5）×2÷2=7÷2
x+1.5=3.5
x+1.5-1.5=3.5-1.5
x=2

②1.2×4-x=2.1
4.8-x=2.1
4.8-x+x=2.1+x
2.1+x=4.8
2.1+x-2.1=4.8-2.1
x=2.7

③2.7x-1.6=38.9
2.7x-1.6+1.6=38.9+1.6
2.7x=40.5
2.7x÷2.7=40.5÷2.7
x=15

④x÷4.5=20
x÷4.5×4.5=20×4.5
x=90