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Write the equation of the line, in slope-intercept form, through the following two points: (-11, -12) (-8, -21) slope: y-intercept: equation:

User Rosely
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1 Answer

10 votes
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Given the points (-11, -12) and (-8,-21), you can calculate the slope of the line that passes through them using the following formula:


m=(y_1-y_2)/(x_1-x_2)
m=(-12-(-21))/(-8-(-11))=(-12+21)/(-8+11)=(9)/(3)=3

The slope is m=3

Now with one of the points and the slope you can determine the equation using the point slope form:


y-y_1=m(x-x_1)

(-11,-12)


\begin{gathered} y-(-12)=3(x-(-11)) \\ y+12=3x+33 \\ y=3x+33-12 \\ y=3x+21 \end{gathered}

The y-intercept is the value of y when x=0, from the equation:


\begin{gathered} y=3\cdot0+21 \\ y=21 \end{gathered}

So,

The slope is 3

The y-intercept is 21

The equation is y=3x+21

User Andrew Matiuk
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