Expert: Bobby Soltani - 1/15/2005

Question
solve the following systems of equations
2x + 3y = 11
x - 4y = 0

possible answers
1. x,y = -1,4
2. x,y = 4,1
3. x,y = 10,-3
4. x,y = 1,3

Answer
Hi Jason,

2x+3y=11
x-4y=0

multiply the second equation by -2 so the x terms will cancel when we add the two equations

2x + 3y = 11
-2x + 8y = 0

add the two equations

0x + 11y = 11
11y = 11
divide both sides by 11
y = 1
from this, we can see that the answer is #2.  Let's check the answer for x to be sure by plugging y=1 into the first equation.
2x+3*1=11
2x = 8
x = 4

It works.  So, the answer is x,y = 4,1

Let me kwow if you have questions.

Bobby