SOLUTION: hey ! I was making some math excercises, but i get blocked with one. it's this: 3x-4(y+7)=x-2 3(-x+y+15)=-6 I got to find X and Y with the addition or substraction metod. I

Algebra ->  Linear-equations -> SOLUTION: hey ! I was making some math excercises, but i get blocked with one. it's this: 3x-4(y+7)=x-2 3(-x+y+15)=-6 I got to find X and Y with the addition or substraction metod. I      Log On


   

Question 719010: hey ! I was making some math excercises, but i get blocked with one. it's this:
3x-4(y+7)=x-2
3(-x+y+15)=-6
I got to find X and Y with the addition or substraction metod.
I will thank you a lot if you, guys, can help me.
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!
Simplify the first one:

3x-4(y+7) = x-2
 3x-4y-28 = x-2
    2x-4y = 26
     x-2y = 13

Simplify the second one:

3(-x+y+15) = -6

Divide both sides by 3

   -x+y+15 =  -2
      -x+y = -17

So the system of equations is

       x-2y =  13
      -x+ y = -17

Add the two equations term by term and get:

         -y = -4
          y = 4

Substitute in 

       -x+y = -17
       -x+4 = -17
         -x = -21
          x = 21

Edwin