5*(x-4)-7*(7-x)-9=13-3*(9-x)

问题描述:

5*(x-4)-7*(7-x)-9=13-3*(9-x)

5*(X-4)-7*(7-X)=13-3*(9-X)
5X-20-49+7X-9=13-27-3X
12X-78=-14-3X
12X+3X=78-14
15X=65
X=13/3