Question 28386
it helps to label your equations. lets say (3x+y=5 is "1" and the other is "2"

solve each equation for y

"1" ----- y=-3x+5
"2" ----- y=2x-10

since both equations both equal "y" you can set them equal to eachother

-3x+5=2x-10
solve this equation for "X"
-5x=-15
x=3

put the value of "3" into the first (or second) equation 

in "1" 3(3)+y=5
9+y=5
y=-4
check your answers in the other equation as well