Question

Find K, so that x=3 is a solution of the equation Kx + 8 =x - 7

Answer 1

put x=3 in the equation to get
3K + 8 = -4
3K = -12
K = -4

Answer 2

KX + 8 = x-7
k(3) + 8 = (3) -7
3k +8 =-4
3k =-8+(-4)
3k=-12
k=-12/3
k=-4