graph these coordinates. (0,-2) (2,0) (4,2) what is the equation of this line

Get some graph paper and draw the x and y axes. Plot your points, join them by a line. Find the gradient(or slope) by choosing two points and putting them in the formula:

\frac{y_2 - y_1}{x_2 - x_1}

You have the y-intercept, from your graph.

Now write

y=mx+c

Replace m by the gradient you obtained, and c by the y intercept.

Voilà! :)