Answer:
View explanation.
Step-by-step explanation:
The question isn't clear on whether or not you are asking if the mom or if the store is owing money to the credit card company. The store owes the full amount paid. The mom owes nothing. You can look at the images for a more detailed explanation, but it is not really needed.
Images from https://www.creditcardinsider.com/blog/happens-credit-card-bill-make-return/
Answer:
Solution : (15, - 11)
Step-by-step explanation:
We want to solve this problem using a matrix, so it would be wise to apply Gaussian elimination. Doing so we can start by writing out the matrix of the coefficients, and the solutions ( - 5 and - 2 ) --- ( 1 )
Now let's begin by canceling the leading coefficient in each row, reaching row echelon form, as we desire --- ( 2 )
Row Echelon Form :
Step # 1 : Swap the first and second matrix rows,
Step # 2 : Cancel leading coefficient in row 2 through ,
Now we can continue canceling the leading coefficient in each row, and finally reach the following matrix.
As you can see our solution is x = 15, y = - 11 or (15, - 11).