解方程. 3/4:5=3/5:x x-25%x=180 2/3x−1/5x=4.9.
问题描述:
解方程.
:5=3 4
:x 3 5
x-25%x=180
x−2 3
x=4.9. 1 5
答
(1)
:5=3 4
:x 3 5
x=5×3 4
3 5
x÷3 4
=3÷3 4
3 4
x=4
(2)x-25%x=180
75%x=180
75%x÷75%=180÷75%
x=240
(3)
x−2 3
x=4.91 5
x=4.97 15
x÷7 15
=4.9÷7 15
7 15
x=10.5.