From the information we have, we know the commission is at 7.25% of all she sells. So we first calculate this from total amount sold.
x =7.25/100 * 4,500
Where x is the commission earned.
x = 7.25 * 4,500 / 100
x = 7.25 * 45
x = 326.25
So commission earned is 326.25 $
We need to add this to her base salary for the week, so:
750 + 326.25 = 1, 076.25
Therefore she earned 1,076 dollars and 25 cents.