system of equations?

Question

i did this a longgg time ago and i totallly for got can someone explain or give me a website to solve these three problems?
1.y=-x - 2
y=x+6

2.x-y=1
x-y=3

3.-x+5y=5
2x+y=4

Answer 1

Question 1
- x - 2 = x + 6
- 8 = 2x
x = - 4

Question 2
x - y = 1 and x - y = 3 ??????

Question 3
-2x + 10y = 10
2x + y = 4--------ADD
11y = 14
y = 14/11

2x + 14/11 = 4
2x + 14/11 = 44/11
2x = 30/11
x = 15/11

Answer is x = 15/11 , y = 14/11

Answer 2

okay, i'm going to show you an example with number 1.

first off, pick one of the two and get x by itself. i'll pick the second one, it really doesn't matter which one you pick.

first, subtract 6 from both sides. you get:
y - 6 = x

then, take what you just got and plug it into the first one in place of x. it will look like this:
y = -(y - 6) - 2

remember to distribute the negative when you're simplyfing. so, go ahead and simplify:
y = -y + 6 -2
y = -y + 4
2y = 4
y = 2

okay, so now you've figured out that y = 2. you can plug 2 in for y into either the first or second equation, i'll pick the second one. so it will look like this:
2 = x + 6

now, all you have to do is simplify again:
-4 = x

so now you have both answers, and depending on how they want you to write out the answer you can do it like this:
x = -4, y = 2

or like this:
(-4, 2)