These equations give x and y in terms of a third variable t. (They are called parametric equations and t is the parameter.)

You can find the cartesian equation connecting x and y directly by eliminating t as follows:

Look at the equations:

They represent the path of a projectile.

Question 10.3.1:

Find the cartesian equation of the path of these projectiles by eliminating the parameter t.

(Ref: Cambridge International AS and A Level Mathematics by Sophie Goldie, Series Editor: Roger Porkess, Hodder Education)