问题
解答题
解比例或方程: 5-
2X+40%X=7.2 5(X-
4:
|
答案
(1)5-
X=2 3
,1 3
5-
X+2 3
X=2 3
+1 3
X,2 3
+1 3
X=5,2 3
+1 3
X-2 3
=5-1 3
,1 3
X=2 3
,14 3
X×2 3
=3 2
×14 3
,3 2
X=7;
(2)2X+40%X=7.2,
(2+0.4)X=7.2,
2.4X=7.2,
2.4X÷2.4=7.2÷2.4,
X=3;
(3)5(X-
)=2,1 3
5X-
=2,5 3
5X-
+5 3
=2+5 3
,5 3
5X=
,11 3
5X÷5=
÷5,11 3
X=
;11 15
(4)4:
=2 3
,x 25
X=4×25,2 3
X×2 3
=100×3 2
,3 2
X=150.