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22 votes
22 votes
I’ve tried many times to answer the question but my teacher keeps saying it’s wrong so can you help me please

I’ve tried many times to answer the question but my teacher keeps saying it’s wrong-example-1
User Oware
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1 Answer

18 votes
18 votes

Let's take the points (2,18) and (6,40) to find the slope (or rate of change) of the linear function:


\begin{gathered} m=(y_2-y_1)/(x_2-x_1) \\ \Rightarrow m=(40-18)/(6-2)=(22)/(4)=(11)/(2) \\ \Rightarrow m=(11)/(2) \end{gathered}

Since the slope is m=11/2 = 5.5, then the hourly fee is $5.5

Now, we can find the maintenance fee by using the slope-intercept formula with the slope that we have and any point on the table. Let's take the point (2,18) to find the maintenance fee:


\begin{gathered} y=mx+b \\ b\colon\text{ maintenance f}e \\ (x,y)=(2,18) \\ m=(11)/(2) \\ \Rightarrow18=(11)/(2)(2)+b \\ \Rightarrow18=11+b \\ \Rightarrow b=18-11=7 \\ b=7 \end{gathered}

we have that b = 7, this means that the maintenance fee is $7.

The equation of this function then is y = 11/2 x + 7

Finally, if we want to rent the bike for 5 hours, we have to make x=5 and solve for y:


\begin{gathered} y=(11)/(2)x+7 \\ x=5 \\ \Rightarrow y=(11)/(2)(5)+7=(55)/(2)+7=27.5+7=34.5 \\ y=34.5 \end{gathered}

therefore, it costs $34.5 to rent the bike for 5 hours.

User David Mimno
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