multiply both sides of the first equation by 8 and both sides of the second equation by 5 to get:
-40x - 56y = 112
-40x - 45y = 90
subtract the second equation from the first to get:
-11y = 22
solve for x to get:
y = -2
replace y with -2 in the first equation to get:
-40x -56y = 112 becomes -40x + 112 = 112
solve for x to get:
x = 0
you have x = 0 and y = -2
replace x and y in both original equations with those values to get:
-5x-7y=14 becomes -5*0 - 7*-2 = 14 which becomes 14 = 14 which is true.
-8x-9y=18 becomes -8*0 - 9*-2 = 18 which becomes 18 = 18 which is true.
the values look good.
your solution is x = 0 and y = -2
if you graph both equations, they will intersect at the point (0,-2) as shown below:
(
