explanation:
we know that box A has 5 times as many pens as box B. if we take away 76 pens from box A, then it will be equal to box B. therefore, we would need to make an equation (where x is box B):
5x - 76 = x
subtract 5x on both sides:
-76 = -4x
divide each side by -4:
x = 19
x would also be box A because box B and box A have the same number of pens
