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1. What is the solution to the system of equations?

{−2x + 6y = −38

   3x − 4y =

 

A.(4, −5)

B.(−5, 4)

C.(1, −6)

D. (−4, −5)

 

2.What is the solution to the system of equations?

x + 3y − z = 6

4x − 2y + 2z = −10

6x + z = −12

 

A. (−4, 0, 12)

B. (−3, 5, 6)

C. (2, 1, −3)

D. (0, −2, −12)

AngelRay  Dec 12, 2017
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2.

 ___ ___ ____ ________________________________ ___ ___ ____ 
x+3y-z=6multiply through by  2  to get2x+6y-2z=12
4x-2y+2z=-10multiply through by  3  to get12x-6y+6z=-30
6x  +z=-12multiply through by -4  to get-24x  -4z=48

 

Add these three equations together to get

 

-10x   =   30             Divide both sides by  -10 .

 

x   =   -3

 

Use this value for  x  in the third given equation to find  z .

 

6(-3)  +  z   =   -12             Subtract  6(-3)  from both sides.

 

z   =   -12 - 6(-3)   =   -12 + 18   =   6

 

Now we can find  y  using the first given equation.

 

-3  +  3y  -  6   =   6

3y   =   15

y   =   5

 

So    x  =  -3 ,    y  =  5 ,    and    z  =  6         smiley

hectictar  Dec 12, 2017

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