please check solve system by addition

jxharmon · 2007-02-10 07:22:14

5x - 3y = 13;
4x - 3y = 11
x=2

4(2) - 3y = 11
8 - 3y = 11
3y= 3
y=1

now what?? how do I prove??

lekkie · 2007-02-10 07:25:07

jxharmon wrote:

5x - 3y = 13;
4x - 3y = 11
x=2
4(2) - 3y = 11
8 - 3y = 11
3y= 3
y=1
now what?? how do I prove??

y = -1

.... pls note

mathsyperson · 2007-02-10 07:33:28

What do you want to know? You've already found the correct values of x and y, it seems like you've done everything that needs to be done.

jxharmon · 2007-02-10 08:06:46

I just want to know if I just plug what I found into the equations to prove my answers??

mathsyperson · 2007-02-10 10:35:22

Oh, OK. Well, you only really need to plug your values into the equation that you didn't use to check that they work.

After you found that x=2, you put that into 4x-3y = 11 to find that y=-1.
That means that to check your answer, you plug them both into 5x-3y = 13.

5*2 - 3*(-1) = 10-(-3) = 13
Therefore your answer is correct.

jxharmon · 2007-02-10 10:49:18

thanks

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