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A line is described by the equation $y-4=4(x-8)$. What is the sum of its $x$-intercept and $y$-intercept?

 Apr 19, 2018
 #1
avatar+17338 
+2

y-4 = 4x-32

y= 4x - 28           when x = 0    you get the y intercept      y = -28

                           when y=  0 you get the x intercept         x = 7            Sum = -21

 Apr 19, 2018
 #2
avatar+21869 
+1

A line is described by the equation $y-4=4(x-8)$.

What is the sum of its $x$-intercept and $y$-intercept?

 

 

\(\begin{array}{|rcll|} \hline y-4 &=& 4(x-8) \\ y-4 &=& 4x-32 \\ 4x-y &=& 32-4 \\ 4x-y &=& 28 \quad & |\quad : 28 \\ \dfrac{x}{7}-\dfrac{y}{28} &=& 1 \\ \dfrac{x}{\mathbf{7}}+\dfrac{y}{\mathbf{-28}} &=& 1 \\\\ \mathbf{7-28} &\mathbf{=}& \mathbf{-21} \\ \hline \end{array} \)

 

The sum is -21

 

laugh

 Apr 19, 2018
edited by heureka  Apr 19, 2018

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