x=12-y sub that for x in other one first divide that one by 2 to make it easier 2x-y=18 2(12-y)-y=18 24-2y-y=18 24-3y=18 minus 24 both sides -3y=-6 divide -3 y=2
D is answer
2. find intersection of x+y=5 and -2x+3y=6 or easiers, just test the intersections wait, they all intersect in the same place this is super easy pick ANY point that is in that reigon and see if it is true
A, if we pick lets say (5,5) that is false for x+y<5 not A
