Solve for the variable y (move the x to the right of equal with changed sign)
M is the coefficient before the x and b is the known number
-3y = -12 - 6x
Since the y can't be negative, multiply every term for -1, therefore change their sign
3y = 6x + 12
To find y, divide both terms for 3

y = 2x+4
Therefore your answer is
y = 2x+4