Given:
Michelle plans on raising $80.
Selling price of each shirt = $10
So far she has raised $20.
To find:
The number of more shirts she needs to sell.
Solution:
Let x be the number of more shirts she needs to sell.
Selling price of one shirt = $10
Selling price of x shirt = $10x
Total raising amount = $(10x + 20)
Michelle plans on raising $80. So,
![10x+20=80](https://tex.z-dn.net/?f=10x%2B20%3D80)
Subtract both sides by 20.
![10x=80-20](https://tex.z-dn.net/?f=10x%3D80-20)
![10x=60](https://tex.z-dn.net/?f=10x%3D60)
Divide both sides by 10.
![x=\dfrac{60}{10}](https://tex.z-dn.net/?f=x%3D%5Cdfrac%7B60%7D%7B10%7D)
![x=6](https://tex.z-dn.net/?f=x%3D6)
So, the required equation is ![10x+20=80](https://tex.z-dn.net/?f=10x%2B20%3D80)
Therefore, the correct option is A.