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4 votes
Elimination:
3x-4y=16
5x+6y=14

User Amir Amir
by
7.1k points

2 Answers

3 votes
okay for this one, i will start with x

3x - 4y = 16
5x + 6y = 14

I will multiply the top row with (-5) and the bottom with (3)
so the new equation is

-15x + 20y = -80
15x + 18y = 42

After canceling (x) the new equation will be

38y = -38

Divide by 38

And you will get -1

Now substitute (-1) to (y) to the old equation ( any of the old equation)
3x- 4(-1)= 16
x = 4

answers ( 4, -1)
User Neonant
by
7.4k points
4 votes

\left \{ {3x-4y=16\ \  \atop 5x+6y=14 \ \ } \right. \\\\ \left \{ {{-15x+20y=-80} \atop {15x+18y=42}} \right. \\+-----\\add\ both \ equations\\\\ 38y=-38\ \ \ | divide\ by\ 38\\\\ y=-1\\\\ 3x=16+4y\\\\ x=(16+4y)/(3)=(16+4*(-1))/(3)=(12)/(3)=4\\\\ \left \{ {{y=-1} \atop {x=4}} \right.
User Dgor
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8.5k points