Question 239152
y=-8x-10 (red line)
-y=9x+9
y=9x/-1+9/-1
y=-9x-9 (green line)
You can solve the 2 equations for x & y or you can graph them & calculate the intersection.
y=-8x-10 
-y=9x+9 add 
----------------------
0=x-1
x=1 ans.
y=-8*1-10
y=-8-10
y=-18 
(x,y)= (1,-18)
{{{ graph( 300, 200, -6, 5, -25, 10, -8x -10, -9x -9) }}} (graph 300x200 pixels, x from -6 to 5, y from -25 to 10, of TWO functions -8x -10 and -9x -9).