Answer:
y = -7
Explanation:
To solve for 'y', we need to isolate it, meaning to separate it from everything else. You move numbers in the equation around by canceling them out, which you do with opposite or reverse operations. (Addition and subtraction are opposites. Division and multiplication are opposites).
First, bring all of the numbers with 'y' to the left, and bring all of the numbers without 'y' to the right. Then isolate y.
7y + 3 = 4y - 18 Move 'y' to the left.
7y - 4y + 3 = 4y - 4y - 18 Subtract 4y from both sides.
7y - 4y + 3 = -18 Notice 4y - 4y cancelled out. Combine like terms on the left. 7y and -4y both have 'y'.
3y + 3 = -18 Move the numbers to the right.
3y + 3 - 3 = -18 - 3 Subtract 3 from both sides.
3y = -18 - 3 +3 and -3 cancelled out. Combine like terms on right.
3y = -21 Cancel out the '3' attached to 'y'.
3y/3 = -21/3 Divide both sides by 3.
y = -21/3 3y/3 becomes just 'y' because 3 ÷ 3 is 1.
y = -7 Answer for y.