12=4x-3y Begin by moving the 4x away from the y. -3y=-4x+12. To get y by itself, divide both sides by -3. y= 4/3x -4. Therefore the slope is 4/3.
Since y=x+3 (given)
Put value of y in equation x+y=(-3)
x+x+3=(-3)
2x=(-6)
x=(-3)
Put x=(-3) in x+y=(-3)
(-3)+y=(-3)
y=0
So, x=(-3)
y=0