Linear Function Review

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Answer explanation

You can eliminate choices 2 and 4 because they have positive slopes. Most helpful place to start is always the y-intercept.

Tags

CCSS.8.EE.C.8B

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• 4

Tags

CCSS.8.EE.B.5

Write the equation of the line passing through the points (-4,-1 and (2,8).

The temperature of a liquid is decreasing at a constant rate. After two minutes of cooling, it was 178 degrees and after five minutes of cooling it was 154 degrees. At what temperature did the liquid start cooling?

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Answer explanation

You are given the slope of 5 and the point (-2, 11). Use the slope intercept form of the line to find b. (y=mx+b).

Substitute all the known variables to find b. Once you find b, you can write the equation m=5, b=21 so y=5x+21.

eMathInstruction has a stockpile of 1,850 Algebra textbooks. They are being purchased at a steady rate of 120 books per week. Write the linear function that models the number of books (b) left after weeks (w).

• 1850=-120w

• b=1850 + 120w

• b=-120w +1850

• 1850 - 120 = w

Tags

CCSS.8.F.B.4

CCSS.HSF.LE.A.2

eMathInstruction has a stockpile of 1,850 Algebra textbooks. They are being purchased at a steady rate of 120 books per week. b represents the number of books left after w, weeks of sales. How would you interpret the statement b (14) = 170?

• 14 books cost $170

• After 170 weeks, there were 4 books left.

• After 14 weeks, there were 170 books left.

• They made a lot of money.

Answer explanation

f(14) means the number of books (output) remaining after 14 weeks (input), which is 170. 14(120)=1680n books sold. If you started with 1850 - 1680 (number of books sold). then you have 170 remaining.

Tags

CCSS.HSF.IF.A.2