Trigonometry question help?

Question

Construct parametric equations describing the graph of the line passing through the following points.

(−18,2) and (9,15)

If x=t+4, find the parametric equation for y.

Answer 1

x= t+4 (9,15) (-18,2)

9=t+4, t = 5, -18=t+4, t=-22

y=at +b

15 =a(5) + b

2 =a(-22) +b subtract to get

13 =27a, a= 13/27

15=5(13/27) + b, b=15-65/17 = 340/27

y=(13/27)t + 340/27 or

27y=13t +340