Answer: she needs to babysit for 3 hours this week.
Explanation:
Let x represent the number of hours that she would babysit in a week.
She currently has $3. If Teresa makes $7.50 an hour babysitting. This means that if she babysits for x hours in a weeks, the total amount of money that she would have saved would be
7.5x + 3
Teresa needs to save $25.50 to go to the movies this weekend. This means that
7.5x + 3 = 25.5
7.5x = 25.5 - 3
7.5x = 22.5
x = 22.5/7.5
x = 3