Answer:
Part a:
1) m = (7 - 4)/(6 - 0) = 3/6 = 1/2
2) BC is perpendicular to CD. The
slope of BC is 1/2, so the slope of
CD is -2.
y - 7 = -2(x - 6)
y - 7 = -2x + 12
y = -2x + 19
2x + y = 19
3) BC || AD, so the slope of AD is 1/2.
(y - 1)/(x - 4) = 1/2
2y - 2 = x - 4
x = 2y + 2
Substitute this into 2x + y = 19:
2(2y + 2) + y = 19
4y + 4 + y = 19
5y = 15
y = 3, x = 8
D is at (8, 3).
