问题
解答题
解方程.
x+3.4=9.2x÷0.3=2.1 3x+2×0.4=21.85(x-4.2)=41.5.
答案
(1)x+3.4=9.2,
x+3.4-3.4=9.2-3.4,
x=5.8;
(2)x÷0.3=2.1,
x÷0.3×0.3=2.1×0.3,
x=0.63;
(3)3x+2×0.4=21.8,
3x+0.8=21.8,
3x+0.8-0.8=21.8-0.8,
3x÷3=21÷3,
x=7;
(4)5(x-4.2)=41.5,
5(x-4.2)÷5=41.5÷5,
x-4.2+4.2=8.3+4.2,
x=12.5.