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Which ordered pair is the solution to the system of equations?

{x+5y=−15

 y=1/5x+1

 Aug 29, 2018
 #1
avatar+98197 
+2

No ordered pairs shown....but...no prob

 

x+5y = −15   

 y =  1/5x+1

 

Rearrange the first as  x  = -15  - 5y

Sub this into the second for  x

 

y  =  (1/5)(-15 - 5y) + 1  simplify

y = -3 - y + 1    add y to both sides

2y  =  -3 + 1

2y = -2    divide both sids by 2

y  = -1

 

So

 

x  = -15 - 5(-1)  =  -15 + 5  =   -10

 

So   (x, y)  = ( -10, -1)

 

 

cool cool cool

 Aug 29, 2018
 #2
avatar+3994 
+2

x+5y=-15, y=1/5x+1. First, rearrange, then we can multiply the second equation by 5, and let the first equation be.

x+5y=-15   x-5y=-5

 

Now, we can subtract! 5y--5y=-15--5, 10y=-10, so y=-1.

We can plug the value of y in the first equation, in order to solve for x.

 

x+5(-1)=-15, x+-5=-15, x-5=-15, x=-10.

 

Thus, the answer is (-10,-1).

 Aug 29, 2018

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