Final answer:
To earn $450 in one week, Gabrielle's weekly sales will have to be $5,625.
Step-by-step explanation:
To find out how much Gabrielle's weekly sales need to be for her to earn $450, we need to consider her 8% commission. 
Let's assume her weekly sales are represented by 'x'. 
To calculate her commission, we multiply her sales by 8%: 
Commission = (8/100) * x. 
Since she has no weekly salary, her total earnings will be equal to her commission. 
Therefore, we can set up the equation: Commission = Earnings = (8/100) * x. 
We need to find the value of 'x' that results in $450 in earnings. 
So, we can write: $450 = (8/100) * x. 
To solve for 'x', we divide both sides of the equation by (8/100): 
x = $450 / (8/100).
In other words, to earn $450 in one week, Gabrielle's weekly sales will have to be $5,625.