Question 816099: I am doing something wrong but i don't know what. My equations are x-5y = 15 and 4x-3y+26 , i multiplied the first equation by -4, then got -23y = 86 . What did i do wrong? Thanks
Found 3 solutions by algebrahouse.com, josgarithmetic, MathTherapy:
Answer by algebrahouse.com(1659)   (Show Source):
You can put this solution on YOUR website! x - 5y = 15
4x - 3y = 26
-4x + 20y = -60 {multiplied first equation by -4}
4x - 3y = 26 {second equation stays the same}
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17y = -34 {added the two equations}
y = -2 {divided each side by 17}
x - 5y = 15 {first equation}
x - 5(-2) = 15 {substituted -2, for y, into first equation}
x + 10 = 15 {multiplied}
x = 5 {subtracted 10 from each side}
x = 5 and y = -2
For more help from me, visit: www.algebrahouse.com
Answer by josgarithmetic(39620)  (Show Source):
You can put this solution on YOUR website! System:
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x-5y=15
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4x-3y=26 (not exactly what you wrote, so not really sure)
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Multiply first equation by -4:
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-4x+20y=-60
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4x-3y=26
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ADD the left hand members and add the right hand members:
Simple to solve as  .
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website!
I am doing something wrong but i don't know what. My equations are x-5y = 15 and 4x-3y+26 , i multiplied the first equation by -4, then got -23y = 86 . What did i do wrong? Thanks
x - 5y = 15 ------ eq (i)
4x - 3y = 26 ------ eq (ii)
- 4x + 20y = - 60 ----- Multiplying eq (i) by - 4 ----- eq (iii)
17y = - 34 ---- ADDING eqs (iii) & (ii)
Solve for y and you should get: 
Do a check after finding x!!
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