Answer: x = -3/k
==============================================
Work Shown:
kx+7 = 4
kx+7-7 = 4-7 .... subtract 7 from both sides
kx = -3
kx/k = -3/k .... divide both sides by k
x = -3/k
The value of k cannot be zero. As the steps show, we are following PEMDAS in reverse to undo each operation to help isolate x. Subtraction is the opposite of addition, and division is the opposite of multiplication.