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Find the value of $B - A$ if the graph of $Ax + By = 3$ passes through the point $(-7,2),$ and is parallel to the graph of $x + 3y = -5.$

 Mar 19, 2021
 #1
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-1

From x + 3y = -5, y = -x/3 - 5, so the slope of the line is -1/3. The slope of the new line is also -1/3, so y = -x/3 + B.  Pugging in x = 2 and y = -7, we get -7 = -2/3 + B, so B = -19/3.

 

Then the line is y = -x/3 - 19/3.  Then 3y = -x - 19, so 3y + x = -19.  We want the right-hand side to be 3, so we mutiply both sides by -3/19: -9/19*y - 3/19*x = 3.  Therefore, A + B = -9/19 - 3/19 = -12/19.

 Mar 19, 2021
 #2
avatar+96 
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That is not correct.

 

Thank you for trying though.

Immaguest  Mar 19, 2021
 #3
avatar+121004 
+1

The slope of  x+ 3y  = -5    is    -1/3

 

So.....the equation  of  a line  with a slope  of  -1/3   and passes  throiugh  the point  (-7,2) is

 

y = (-1/3)(x - - 7)   +  2            simplify

 

y = (-1/3)x - 7/3  + 6/3

 

y  = (-1/3)x  - 1/3                 multiply  through  by  3

 

3y  = -x   - 1               add x to both sides

 

x + 3y  =  -1

 

B  = 3    A  =1

 

B  - A  =   2

 

Here's a graph  :   https://www.desmos.com/calculator/qhp2legobe

 

 

cool cool cool

 Mar 19, 2021
 #4
avatar+96 
0

It says that that is incorrect.

 

Thank you for trying.

Immaguest  Mar 21, 2021
 #5
avatar+96 
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Pleae help!

 Mar 22, 2021

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