Question

Clare was solving an equation, but when she checked her answer she saw her solution was incorrect. She knows she made a

mistake, but she can't find it. Where is Clare's mistake?
12(5 + 2y) = 4y - (5 – 9y)
72 + 24y = 4y - 5 - 9
72 +24y = -5y - 5
24y = 5y - 77
29 y = -77
-77

Answer 1

When distributing the negative to the (5-9y) you need to distribute it to both the 5 and the -9 so your 9 should be positive now. So it should be 72+24y = 4y-5+9y