Answer:
Ashley should have added 4.5 to both sides.
Explanation:
Given expression:
![-4.5+m=17](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t1n76flto082hyfcavk3ymgmql6rspcotz.png)
Ashley's solution:
Subtracted 4.5 to both sides and got,
![m=12.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8eve1hljauegkbgb2kmadx94nozuhttah2.png)
Correct solution:
Adding 4.5 to both sides.
![-4.5+m=17](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t1n76flto082hyfcavk3ymgmql6rspcotz.png)
![+4.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8rnki63w700dhf2qpc4vfyv2mmqk468j21.png)
∴
![m=21.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t4xt3e9yanzhmuf6inhxz7kt12wqfgm3sj.png)
Error made by Ashley was subtracting 4.5 both sides. Instead he should have added 4.5 both sides.