Respuesta :

Answer:

The solution is

[tex]x=\frac{9}{11}[/tex]

[tex]y=\frac{17}{11}[/tex]

Step-by-step explanation:

We have the system:

-4x+6y=6

-7x+5y=2

I would like to solve this by elimination because I don't feel like rearranging both equations and they both have the same form which is crucial in elimination. The only thing is I will need opposites in a column (where the variable are).

So I'm going to focus on the x's.  I want the x part to be opposites.

I know if I multiply the first equation by 7 I will get -28x plus... and if I multiply the last equation by -4 I will get 28x plus... .

28x and -28 are opposites and we all know what happens to opposites when you add them. They zero out; cancel out.  That is -28x+28x=0.

So let's multiply first equation by 7 and

multiply bottom equation by -4:

-28x+42y=42

28x-20y=-8

----------------------We are ready to add the equations:

  0+22y=34

      22y=34

Divide both sides by 22:

          y=34/22

Reduce the fraction:

         y=17/11              (I divided top and bottom by 2.)

Now if y=17/11 and -4x+6y=6, we can find x by inserting 17/11 for y in the second equation I wrote in this sentence.

[tex]-4x+6\cdot \frac{17}{11}=6[/tex]

Perform the simplification/multiplication of 6 and 17/11:

[tex]-4x+\frac{102}{11}=6[/tex]

Subtact 102/11 on both sides:

[tex]-4x=6-\frac{102}{11}[/tex]

Find a common denominator:

[tex]-4x=\frac{66}{11}-\frac{102}{11}[/tex]

[tex]-4x=\frac{-102+66}{11}[/tex]

[tex]-4x=\frac{-36}{11}[/tex]

Divide both sides by -4:

[tex]x=\frac{-36}{-4(11)}[/tex]

Reduce 36/4 to 9:

[tex]x=\frac{9}{11}[/tex]

[tex]x=\frac{9}{11}[/tex]

The solution is

[tex]x=\frac{9}{11}[/tex]

[tex]y=\frac{17}{11}[/tex]