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Solve the system by using a table

{-0.6x-0.6y=-0.6

{0.5x-0.3y=2.7

 

A. (4,-3)

B. (-3,4)

C. (-4,-3)

D. (-3,-4)

 Oct 14, 2015
edited by Paypay  Oct 14, 2015

Best Answer 

 #1
avatar+111360 
+5

Solve the system by using a table

{-0.6x-0.6y=-0.6

{0.5x-0.3y=2.7

 

A. (4,-3)

B. (-3,4)

C. (-4,-3)

D. (-3,-4)

 

======================================================================================

I'm not sure how to solve "using a table"  [ maybe someone else knows  ???]

 

If we mutiply both equations by 10 to clear the decimals, we have

 

5x - 3y = 27    .....and.....

 

-6x - 6y = -6      divide through by -6   and we have      x + y  = 1    which implies that, y =  1 - x

 

Substituting this into the first equation, we have

 

5x - 3(1 - x)  = 27   simplify

 

5x - 3 + 3x =  27

 

8x -3 = 27

 

8x = 30

 

x = 30/8  =  15/4 =  3.75       and y = 1 - 15/4 =  -11/4   = -2.75

 

Mmmmmm...it doesn't look like any of these answers work!!!   [I checked this with WolframAlpha....my solutions are correct  !!! ]

 

 

 

cool cool cool

 Oct 14, 2015
 #1
avatar+111360 
+5
Best Answer

Solve the system by using a table

{-0.6x-0.6y=-0.6

{0.5x-0.3y=2.7

 

A. (4,-3)

B. (-3,4)

C. (-4,-3)

D. (-3,-4)

 

======================================================================================

I'm not sure how to solve "using a table"  [ maybe someone else knows  ???]

 

If we mutiply both equations by 10 to clear the decimals, we have

 

5x - 3y = 27    .....and.....

 

-6x - 6y = -6      divide through by -6   and we have      x + y  = 1    which implies that, y =  1 - x

 

Substituting this into the first equation, we have

 

5x - 3(1 - x)  = 27   simplify

 

5x - 3 + 3x =  27

 

8x -3 = 27

 

8x = 30

 

x = 30/8  =  15/4 =  3.75       and y = 1 - 15/4 =  -11/4   = -2.75

 

Mmmmmm...it doesn't look like any of these answers work!!!   [I checked this with WolframAlpha....my solutions are correct  !!! ]

 

 

 

cool cool cool

CPhill Oct 14, 2015

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