Apply the distributive property. 9 a − 4 ( 2 a ) − 4 ⋅ 5 9 a - 4 ( 2 a ) - 4 ⋅ 5 Multiply 2 2 by − 4 - 4 . 9 a − 8 a − 4 ⋅ 5 9 a - 8 a - 4 ⋅ 5 Multiply − 4 - 4 by 5 5 . 9 a − 8 a − 20 Subtract 8 a 8 a from 9 a 9 a .
15% off means 85% on so I would use .85x · 6 = total monthly cost to represent this problem. The dot represents times (I did not want to confuse things by using x)
