Question

sorry the picture is blurry. I don't understand subsitution and need help. please help me I'm failing math and this will hopefully get my grade up

Answer 1

Okay so what you need to do is find the value of x or y. Substitute x or y for 0. After you do that, you'll be left with x on one side and y on the other. That's perfect. If x is alone, you want to substitute that into the equation, In parentheses. Then when you solve for the other term, you'll actually get a number answer. Then put that into the equation and substitute it where it should go, then solve and you'll get the second number

Answer 2

Assuming you want us to answer question 12.
11x - 7y = -14 
x - 2y = -4 

From the second equation, you can find x by adding 2y to both sides.
x = 2y - 4

Now that you've found what x is, go back to the first equation 11x - 7y = - 14
But now, wherever you see x in this, substitute in what you found for x. 
Our value for x is 2y - 4. 
11(2y - 4) - 7y = -14
Expand and simplify
22y - 44 - 7y = -14
15y - 44 = -14
15y = 30
y = 30/15 = 2

Now we know what y is, lets find x as a number.
Use what we found as x to find it as a number (x = 2y - 4), but substituting in 2 wherever we see 'y'.
So x = 2(2) - 4
= 4 - 4 = 0

So x = 0 and y = 2