求未知数x 5x﹣4.5×2=0.5; =:5.
6-3= 3+3= 7-5= 5+2=
9-4= 9-5= 4+5=
10-4= 10-6= 4+6=
5+2= 7-5= 7-2=
4+1= 5-1= 5-4=