Answer:
$540
Step-by-step explanation:
Let s be Alexandria's salary before taxes.
Let t be her take-home after taxes = $378
The question says her take-home is 7/10 of her salary before taxes
So to calculate what her salary was before taxes:
s x (7/10) = $378
We divide both sides by 7/10
S = 378 ÷ 7/10
S = 378x10/7
S = 3780/7
S = 540
Therefore from the calculations above, her salary before taxes was $540