Gwen, tristan, and keith like to work out at the gym. they each have an app on their phone that estimates the calories they burn. by the time tristan and keith started exercising, gwen had already burned 100 calories. gwen burns 10 calories every minute, tristan burns 125 every 10 minutes, and keith burns 300 calories every 30 minutes. let x represent the number of minutes since tristan and keith started exercising and y represent the number of app-estimated calories burned. part a

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

answer: c

because if you look at the chart you can see a pattern and compare it to the question he simplify out your

but i think the formula is f(x)=6x