How many possible solutions could f(x) = 6x^3 + 8x^2 - 7x -3 have?

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b

What is the slope of the line that contains the points (-2,1) and (0,-3)