3x+5x+4-x+7=88
Combining like terms
3x+5x-x+4+7=88
8x-x+11=88
7x+11=88
Subtract 11 to each side
7x+11-11=88-11
7x=77
Divided 7 to each side
7x/7=77/7
x=11
Check:
3x+5x+4-x+7=88
Substitute x with 11
3(11)+5(11)+4-11+7=88
33+55+4-11+7=88
88+4-11+7=88
92-11+7=88
81+7=88
88=88. As a result, x=11. Hope it help!