Linear Equations

Starting at sunrise, the temperature rose 2.5⁰ every hour. After 8 hours, the temperature was 67⁰. Write an equation in point-slope form to model the temperature, y, after x hours after sunrise. If sunrise was at 6:00 AM, what is the temperature at noon?

•   y+67=2.5(x+8) ; the temperature was 62⁰ at noon

•  y−67=2.5(x−8); the temperature was 62⁰ at noon

•  y−67=2.5(x−8); the temperature was 77⁰ at noon

•  y−8=2.5(x−67); the temperature was 77⁰ at noon

The aquarium is draining a large fish tank. The pump they are using can drain 24 gallons per hour. After 3 hours, there are 78 gallons left in the tank. Write an equation in slope-intercept form to model the water left in the tank, y, after x hours of draining. How many gallons were originally in the tank?

Ben and Julia rented a truck from the same company to move to college. Ben drive 150 miles and paid $64.95 while Julia drove 84 miles and paid $45.15. What is the slope and what does it represent in context to the situation.

• m = 0.30; it represents the cost per mile.

• m = 0.30; it represents the initial fee for the moving truck

• m = 19.95; it represents the initial fee for the moving truck

• m = 3.33; it represents the cost per mile.

Allie orders candles from an online company that offers flat rate shipping. She placed an order for 4 candles for $35. A few months later, she placed an order for 12 candles for $95. Write an equation in point-slope form to model the total cost, y, for ordering x candles. How much is shipping?

Which equations form a linear function?

Which equation represents the graph of the function with point (-2, 5) and slope of 3?

What is the equation and slope of the line shown on the grid?

• y = 6; slope is -1

• x = 6; slope is zero

• y = 6; slope is 6

• x = 6; slope is undefined

Which equation represents y = -3x + 5 in point-slope form?

Which equation best represents the relationship between x and y in the table shown?

• y= 5x+5

• y=1/5x+5

• y=15x+5

• y=10x+5

Bob has $150 in his savings account and saves $40 per month.

• y=150 + 40

• y=40x + 150

• y=150x + 40