PLEASE HELP Which operations can be applied to a matrix in the process of Gauss-Jordan elimination? (choose ALL correct answers)

A. replacing a row with twice that row
B. replacing a row with the sum of that row and another row
C. replacing a row with three times another row
D. swapping rows
E. replacing a row with the absolute values of that row

Which function can be used to model the monthly profit for x trinkets produced? f(x) = –4(x – 50)(x – 250) f(x) = (x – 50)(x – 250) f(x) = 28(x + 50)(x + 250) f(x) = (x + 50)(x + 250)

What are the solutions of the following system? y=-2x^2 y=x-2

The students at jefferson middle school are raising money for a charity by selling t-shirts and hats. the number of t-shirts sold was 3 times the number of hats. the profit was $5 for each t-shirt sold and $2.50 for each hat sold. the students raised $840 for the charity. they used the system below to analyze their success and found the solution to be (144, 48). 5x+2.50y=840 x=3y how much did they earn from t-shirt sales?