（x+3.5）×2=14 X+3.5=14÷2 X+3.5=7 X+3.5-3.5=7-3.5 X=3.5
X+3.5=7 X=3.5
（x+3.5）×2=14 两边除2X+3.5=7X=7-3.5=3.5
