Line a: (–1, 2), (1, 8)
Line b: (–3, –4), (2, 11)
ma = 8 − 2
1 − (− 1)
= 6
2
= 3
mb = 11 − (−4)
2 − (− 3)
= 15
5
= 3
Slope of the line through (1, 8) and (2, 11)
m = 11 − 8
2 − 1
= 3
1
= 3
How many points of intersection are there between line a and line b?
zero
one
two
infinitely many