Given: x + 2y = - 6. Solve for x. What is the coefficient of y?

Solving for x you need to just move the 2y to the other side. Since it is a positive 2y to get rid of it you need to subtract 2y on both sides. and you are left with x = - 2y - 6.

the coefficient of y is just the number before the y. so depending on what side of the equation the y is on it could be either 2 or - 2