a.
one solution
b.
no solution
c.
an infinite number of solutions

                                            5x + 7 =  1/2 (10x + 12)

Eliminate the parentheses
on the right side:                  5x + 7 = 1/2(10x) + 1/2(12)

                                             5x + 7 =    5x       +      6

Subtract  5x  from each side:      7  =   6

There is no number for 'x' that can make  7 = 6 .
So there is no solution.

Idon’t know this and this isn’t middle school work