1. ## Systems of Equations

I am entering precalculus but in order to finish the summer packet, I have to go all the way back to algebra. I need some refreshing on system of equations.

If you could explain how to do these problems and give me a summary of how to do the different methods, it would be extremely helpful.

These are the specific questions I am having trouble with, if you explain how to do them it would be a big help. Thanks.

1) 5x+4y=6 -2x-3y=-1

2) -2x+y=8 y=-3x-2

Any help would be appreciated, thanks in advance.

2. Originally Posted by Mp5xm8
2) -2x+y=8 y=-3x-2
One method is substitution. You take one equation and solve for one of the variables. I picked the second problem because the second equation is already solved for one of the variables (y). You plug this into the 1st equation for y like this:
-2x + y = 8
-2x + (-3x - 2) = 8
-5x - 2 = 8
-5x = 10
x = -2

Then you take this result and plug it into the 2nd equation:
y = -3x - 2
y = -3(-2) - 2
y = 6 - 2
y = 4

01

EDIT: too early in the morning...

3. Thanks, for your explanation, now i just need some help with the other equation.

4. One method for exercise (1) would be addition (or elimination). You could, for instance, multiply the first equation by 3 and the second by 4, and add the results.

What method(s) did you try, and where did you get stuck?