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A line through the points( 2, -9)  and (j, 7)  is parallel to the line 2x +3y = 21 . What is the value of j ?

 Mar 20, 2021
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2x + 3y  = 21

3y  =  -2x +21

y = (-2/3)x  + 7

The  slope of  this line =  -2/3....so a parallel line has the same  slope

 

So

 

(-9 - 7)  / ( j - 2)  = -2/3

 

-16 / ( j - 2)  =  -2/3             cross-multiply

 

-16 * 3   =  -2 ( j - 2)

 

-48   =  - 2j + 4

 

-48 - 4  =  - 2j

 

-52  = -2j

 

j =  -52 / -2   =  26

 

 

cool cool cool

 Mar 20, 2021

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