Answer:
X=-4, y=-5
Explanation:
Y=2X+3
y=-x-9
substitute by inserting y value of 2nd equation (-x-9) into y value of 1st equation:
-x-9=2x+3
-x-9+9=2x+3+9
-x=2x+12
-3x=12
x=-4
solve for y by inserting x value (2) into either equation
y=2x+3
y=2(-4)+3
y=-8+3
y=-5
check answer by inserting x and y into either equation to make sure they equal:
y=2x+3
-5=2(-4)+3
-5=-8+3
-5=-5
or
y=-x-9
-5=-(-4)-9
-5=-5