SOLUTION: -5x+3y = 11 3x+2y = -21 i have gotten the answer from the solver, but i am lost on working out the problem since the solver doesnt show all the work.. can you please finish

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: -5x+3y = 11 3x+2y = -21 i have gotten the answer from the solver, but i am lost on working out the problem since the solver doesnt show all the work.. can you please finish       Log On


   

Question 70237: -5x+3y = 11
3x+2y = -21
i have gotten the answer from the solver, but i am lost on working out the problem since the solver doesnt show all the work..
can you please finish the problem showing all the work so i can try and follow.
thank you
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
       
            -5x+3y = 11
             3x+2y = -21

First you need to cancel out one variable so you can solve for the other, I chose x since they have opposite signs. You need to make the bottom variable of x equal to the top variable so they cancel out. You can multiply the top by 3 and the bottom by 5.
            3(-5x+3y = 11)
             5(3x+2y = -21)

It then becomes 
            -15x+9y = 33
             15x+10y = -105

Now add the individual components together, for instance add -15x and 15x to get 0x and so on to get
             0x+19y=-72


Now solve for y
19y=-72Divide both sides by 19.
y=-72%2F19=-3.78947368421053Approximately


Now plug this y value into either equation to solve for x
3x%2B2%28-72%2F19%29+=+-21
3x-144%2F19=-21Multiply by 2
3x=-21%2B144%2F19Add 144/19 to both sides
3x=-399%2F19%2B144%2F19Find common denominator
3x=-255%2F19Simplify
x=-255%2F57=-4.47368421052632Approximately
So x=-255/57 and y=-72/19