问题 解答题
求未知数X的值:
①3.2X-4×
1
4
=
1
5

②24:X=9:5
③X:18=54:3
④0.5X-
7
8
=1.625.
答案

(1)3.2X-4×

1
4
=
1
5

3.2X-1=

1
5

3.2X-1+1=

1
5
+1,

3.2X÷3.2=1.2÷3.2,

x=0.375;

(2)24:X=9:5,

9X=24×5,

9X÷9=120÷9,

X=13

1
3

(3)X:18=54:3,

3X=18×54,

3X÷3=972÷3,

X=324;

(4)0.5X-

7
8
=1.625,

0.5X-

7
8
+
7
8
=1.625+
7
8

0.5X÷0.5=2.5÷0.5,

X=5.

单项选择题
单项选择题