Question 1157002

1. Solve the system by substitution.
  A) 3x+4y=11.     B) 3x+2y=6
     -8x-y=19.         2x+5y=-7


2. Solve the system using the addition method
  A)11x-5y=10.      B)10x-4y=7
    13x-7y=2.       B)4x-y=-5

I need to show the work and I don't understand how to do them.
<pre>This is how B) needs to be done:
3x + 2y = 6 ------ eq (i)
2x + 5y = - 7 ---- eq (ii)
x - 3y = 13 ------ Subtracting eq (ii) from eq (i)
x = 13 + 3y ------ eq (iii)
3(13 + 3y) + 2y = 6 ------ Substituting 13 + 3y for x in eq (i)
39 + 9y + 2y = 6
11y = - 33
{{{highlight_green(matrix(1,5, y, "=", (- 33)/11, "=", - 3))}}}
Now, do you think you can find y?