求未知数x.x+2.5-y=7-y y+x+13.2=18+y 学到方程了,请用我学方程的方法解决,

x+2.5-y=7-y
x+2.5=7-y+y
x+2.5=7
x=7-2.5
x=4.5
y +x+13.2=18+y
x+13.2=18+y-y
x+13.2=18
x=18-13.2
x=4.8