问题
解答题
解方程. (1)χ-
(2)42:
(3)5x-0.4=75% |
答案
(1)χ-
χ=3 5
,6 5
x=2 5
,6 5
x÷2 5
=2 5
÷6 5
,2 5
x=3;
(2)42:
=χ:3 5 5 7
x=42×3 5
,5 7
x÷3 5
=30÷3 5
,3 5
x=50;
(3)5x-0.4=75%,
5x-0.4+0.4=75%+0.4,
5x÷5=1.15÷5,
x=0.23.