Question 22315
1. -8+6x=-74
      6x = -66
       x = -11
2. 
1st: 2x+3y = -15
2nd: 8x+5y = -25
To eliminate the "x's" you multiply the 1st by "4"
and then subtract it from the 2nd, as follows:
new 1st: 8x+12y = -60
new 2nd: 0x-7y = 35
Solve for "y":
          y = -5
Substitute into the original 1st equation:
  2x + 3(-5) = -15
  2x + -15 = -15
        x  = 0
Check x=0 and y=-5 in the original 2nd:
   8(0)+5(-5) = -25
         -25 = -25

So, the answer is x=0, y= -5
3rd Problem: Don't know what you are asked to do with this.

cheers,
Stan H.