Suppose you graphed every single point of the form (2t + 3, 3-3t). Suppose you graphed every single point of the form $(2t + 3, 3-3t)$. For example, when $t=2$, we have $2t + 3 = 7$ and $3-3t = -3$, so $(7,-3)$ is on the graph. Explain why the graph is a line, and find an equation whose graph is this line.

$$x=2t+3, y=3-3t$$
$$(x-3) \frac{3}{2}=3t$$
$$y=3-3t=3-\frac {3}{2} x +\frac{9}{2}$$
$$y=-\frac {3}{2} x+ \frac{15}{2}$$
Tip: "Parametric equations of a curve express the coordinates of the points of the curve as functions of a variable, called a parameter. For example, $x= \cos t$ and $y= \sin t \ $are parametric equations for the unit circle, where t is the parameter."
