(150+240-X)/X=0.3 x等于多少

问题描述:

(150+240-X)/X=0.3 x等于多少

390-x=0.3
390=1.3x
x=300那是除以x哎,怎么会是390-x呢???不好意思,右边少打了个x是390-x=0.3x