解方程. 50%x+x=150 x÷10%=300 3%x+20=60×5/6 4/5x-12.6=40%x.
问题描述:
解方程.
50%x+x=150
x÷10%=300
3%x+20=60×
5 6
x-12.6=40%x. 4 5
答
(1)50%x+x=150,
1.5x=150,
1.5x÷1.5=150÷1.5,
x=100;
(2)x÷10%=300,
x÷0.1=300,
x÷0.1×0.1=300×0.1,
x=30;
(3)3%x+20=60×
,5 6
0.03x+20=50,
0.03x+20-20=50-20,
0.03x=30,
0.03x÷0.03=30÷0.03,
x=1000;
(4)
x-12.6=40%x,4 5
0.8x-12.6=0.4x,
0.8x-12.6-0.4x=0.4x-0.4x,
0.4x-12.6=0,
0.4x-12.6+12.6=0+12.6,
0.4x=12.6,
0.4x÷0.4=12.6÷0.4,
x=31.5.