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21 votes
WRITING LINEAR EQUATIONS FROM WORD PROBLEMS Addison painted her room. She had 50 square meters to paint, and she painted at a constant rate. After 2 hours of painting, she had 35 square meters left. Write an equation for the relationship between the area and number of hours.

User Matthew Mark Miller
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1 Answer

19 votes
19 votes

Let:

y = total square meters to paint

x = number of hours


\begin{gathered} \text{Write the equation in the slope intercept form:} \\ y(x)=mx+b \\ \text{ In this case:} \\ y(x)=50-mx \\ \text{After 2 hours she had 35 square meters left, so:} \\ x=2 \\ y(2)=35=50-2(m) \\ 35=50-2m \\ \text{Solve for m:} \\ 15=2m \\ m=(15)/(2)=7.5 \\ So\colon \\ y(x)=50-(15)/(2)x \end{gathered}

User EldarGranulo
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