17. Because 7 plus 4 equals 11 and if you add 6 you get 17
I would solve the first equation for x and then sub that value into x in the second equation. That's the easiest way. x - 2y = 3 solved for x is x = 2y+3. Now sub that in for x in the second equation: 5(2y+3)+3y=2 and 10y + 15 + 3y = 2. 13y = -13, and y = -1. Now sub that y value into either equation to solve for x: x = 2(-1) + 3 gives us an x value of x = 1. Therefore, your solution to this system is (1, -1), first choice above.
AD is perpendicular to BC so slope Ad = -1/slope of BC
Slope of BC = (2 - (-1)) / (- 6- 3) = 3 / -9 = -1/3
So slope of AD = -1 / (-1/3) = -3/-1 = 3 Answer
The slope should be one over two.