Save quadratic formula results as variables

[wheelercj]

Is your feature request related to a problem? Please describe.
The quadratic formula results cannot be directly used with anything else. They have to be retyped.

Describe the solution you'd like
Before the quad function ends, save the two results to variables such as quad_a and quad_b, and tell the user about these variables.

e.g.

>> quad(-1, -2, 4)
quad_a = 1.236068
quad_b = -3.236068

Would be better instead of:

>> quad(-1, -2, 4)
= 1.236068 or -3.236068