5x²+13x-4-17x²-7x+19+15x²+5x-21x-7=
=5x²+15x²-17x² +(13x-7x+5x-21x) -4-7+19=
=3x²-10x+8
You have to swap to (x,y) to (y,x) and make the y negative so it would be (-y,x) and since it’s counterclockwise it would be in the 4th quadrant
9/19 - 3/14
= 126/140 - 57/140
= 69/140
A should be the right answer. Hope this helped!