Quiz - Slope & Y-Intercept in Linear Models

Jimmy Joe Bob won a jar full of candy. A really big jar. And there is A LOT of candy in this jar. 6 days after winning this jar of candy there were 580 pieces of candy inside. On day 11 there were still 460 pieces of candy! The amount of candy in this jar, C(x), changes depending on the number of days, d, since JJB won the jar. Describe what is happening to the amount of candy as days go by.

• The amount of candy is increasing.

• The amount of candy is descreasing.

• The amount of candy is staying the same.

• The amount of candy doesn't depend on the number of days.

Determine the slope, or rate of change, for this candy-in-a-jar situation. Show how you determined this value.

• m = -24

• b = -24

• m = -120

• b = -120

What does the slope mean in context?

• The amount of candy is decreasing by 24 pieces of candy per day.

• The amount of candy is decreasing by 120 pieces of candy.

• The amount of candy is decreasing by 120 pieces of candy per day.

• The amount of candy decreased 120 pieces in 5 days.

Determine the y-intercept, or initial value, for this jar of candy story. Show how you determined this value.

• m = 144

• b = 144

• b = 436

• b = 724

Explain what the y-intercept means in context.

• When JJB won the candy jar, there were 724 pieces of candy in the jar.

• When JJB won the candy jar, there were 580 pieces of candy in the jar.

• Jimmy Joey Bobby likes to eat a lot of candy and might have a problem. And a cavity, or seven.

• When there are 0 days of candy eating, JJB will have 724 jars of candy.

Determine the slope-intercept equation that models the number of pieces of candy in the jar, C(x), based on the number of days, d, since winning the jar. Show how you determined this equation.

• C(x) = -120x + 580

• C(x) = 24x + 724

• C(x) = 724 - 24x

• C(x) = 700 - 24x

Using this candy-in-a-jar story, find the value of C(22) and explain what it means in context.

• C(22) = 1252, so on day 22, there were 1252 pieces of candy in the jar.

• C(22) = 29.25, so it took 22 days until there were about 29 pieces of candy left in the jar.

• C(22) = 196, so there were 22 pieces of candy left in the jar after JJB ate 196 pieces.

• C(22) = 196, so after 22 days there were 196 pieces of candy left in the jar.

Which equation models the line on the graph?

• f(x) = 3x + 2

• f(x) = -2x + 3

• f(x) = 2x + 3

•  f(x) = 2 + 3x

Choose the line on the graph that models the equation, f(x) = 3x - 3.

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Determine the equation in slope-intercept form for a line that passes through the points (-1, 10) and (6, 45). Show how you determined the equation. DO NOT include any spaces when you type your answer.