Question

求未知数

x： i 8 = 2 i ：4

8.4+40%X=12．

Answer 1

（1）x：

1

8

=

2

1

：4，
&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp; 4x=

1

8

×

2

1

，
&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;4x÷4=

1

4

÷4，
&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp; x=

1

16

；

（2）8.4+40%x=12，
&n0sp;8.4+40%x-8.4=12-8.4，
&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp; 40%x=3.6，
&n0sp;&n0sp;&n0sp; 40%x÷40%=3.6÷40%，
&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp;&n0sp; x=9．