Writing Equations in Two Variables

 $y=250+7.5x$  An athlete burns 250 calories lifting weights. The athlete then works out on an elliptical training and burns 7.5 calories each minute. Which equation represents the total number of calories burned during the workout/

•  $y\ =\ 250-7.5x$  

•  $y=250+7.5x$  

•  $y=250x-7.5$  

•  $y=250x+7.5$  

Marissa is saving money. She plans to buy her own I-Phone. She deposits $75 in the bank and plans to add $50 each week. Which equation represents the total amount of money she saved each week?

• $y=75x-50$

• $y=50-75x$

• $y=50x-75$

• $y=50x+75$

A gym charges $30 to join. The monthly fee is $15. Which graph shows the total cost of the gym membership.

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Teresa's cell phone charges her $44.95 a month and $0.25 per text message. What is the independent and dependent variable in this situation?

• Independent: number of months (x), dependent: Total charges (y)

• Independent: number of text messages (x) , dependent: Total charges (y)

• Independent: total charges (x), dependent: number of text messages (y)

• Independent: number of text messages (x); dependent: number of months (y)