Below is a Wolfram .CDF that will allow you to graph a quadratic function of the form $y=ax^2+bx+c$ on the standard graph. Just enter the values for $a, b, \mbox{ and } c$ in the boxes below.
Below is a Wolfram .CDF that will allow you to graph a linear function of the form Ax+By=k on the standard graph. Just enter the values for A, B, and k in the boxes below.