(23-X)/(30-X)=4分之3.(23-x)/(30-x)=3/4(23-x)×4=(30-x)×392-4x=90-3x4x-3x=92-90x=2

问题描述:

(23-X)/(30-X)=4分之3.
(23-x)/(30-x)=3/4
(23-x)×4=(30-x)×3
92-4x=90-3x
4x-3x=92-90
x=2