SOLUTION: Solve each system of equation below using mulitiplication with the addition method. 1) 5x-2y=4 Shown work:3(5x-2y=4) 15x-6y=12 3x+y=9 5(3x+y=9) 15x

Algebra ->  Systems-of-equations -> SOLUTION: Solve each system of equation below using mulitiplication with the addition method. 1) 5x-2y=4 Shown work:3(5x-2y=4) 15x-6y=12 3x+y=9 5(3x+y=9) 15x      Log On


   

Question 410723: Solve each system of equation below using mulitiplication with the addition method.
1) 5x-2y=4 Shown work:3(5x-2y=4) 15x-6y=12
3x+y=9 5(3x+y=9) 15x+5y=45
-1y=57
-57, i Knew this was not right because my teacher has a clomn of awnsers and this did not match to any y values, Thank you for your help!!!!!

Found 2 solutions by scott8148, ewatrrr:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
if you want to eliminate the x terms by addition , one of your multipliers must be negative

the sum of your multiplied equations is ___ 30x - y = 57 ___ the x's were not eliminated because they had the same sign


HINT : the y terms are easier to eliminate because they already have different signs
___ and you only have to multiply one equation

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi



  5x-2y=4  

  3x+y=9 



  15x-6y=12  

  15x+5y=45   |all good work



   15x-6y=12  

  -15x-5y=-45  |need to multiply thru with -1 in the 2nd Eq to eliminate x

      -11y = -33

         y = 3  and x = 2 (from 2nd Eq on top 3x = -y + 9, x = 6/3)



CHECKING our Answer***

 3*2 + (3) = 9

&5*2 -2*3 = 4