Is this a direct variation? for #1

What value is a discontinuity of x squared plus 8 x plus 4, all over x squared minus x minus 6?

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.