Question

write in parametric form the equation of the line that joins (1,-2) and (3,0)

Answer 1

dy/dx = 2/2 = 1
so y = x + b
0 = 3 + b
b = -3

so y = x - 3
if x(t) = k t for example
then y(t) = x(t) - 3
y(t) = k t - 3