To factor x^2+8x+16, you have to find two numbers that add up to 8 and multiply to your constant, 16. 4 and 4 fit these requirements so you can factor them as (x+4)(x+4). Hope I explained it okay :)
For problems 29 - 31 the graph of a quadratic function y=ax^2 + bx + c is shown. tell whether the discriminant of ax^2 + bx + c = 0 is positive, negative, or zero.