solve the system by addition:
-5x-9y = -5
x+5y=-15
I've tried this one over and over, but I can't seem to get the right answer. I don't even really know where to start. each time i try to do it, i go about it a little differently and i'm completely lost, pls help!!
from the second equation:
x=-5y-15
now sub that back in the first one:
-5(-5y-15)-9y=-5
25y+75-9y=-5
16y=-5-75
16y=-80
y=-5
now sub that back into x=-5y-15
x=-5(-5)-15
x=25-15
x=10
OR
first equation .....
-5x - 9y = -5
second equation times 5 ...
5x + 25y = -75
add them, the x's are eliminated
16y = -80
y = -5
substitute that in one of the originals, etc