Answer: her sales last week was $4300.
Explanation:
Let x represent her her sales in a week.
Danielle earns a 8.25% commission on everything she sells at the electronics store where she works. This means that the commission she gets if she makes sales of $x is 0.0825x
She also earns a base salary of $675 per week. The expression for the total earnings for a week in which she made sales of $x would be
0.0825x + 675
if her total earnings for last week were $1,029.75, it means that
0.0825x + 675 = 1029.75
0.0825x = 1029.75 - 675
0.0825x = 1029.75 - 675
0.0825x = 354.75
x = 354.75/0.0825
x = $4300