(7x+70)/(3x+70)=7/4
问题描述:
(7x+70)/(3x+70)=7/4
答
(7x+70)/(3x+70)=7/4
两边乘以4*(3x+70)
4(7x+70)=7(3x+70)
28x+280=21x+490
28x-21x=490-280
7x=210
x=210/7
x=30