Write a quadratic equation having the given numbers as solutions -7 and -4

X+_=-7 and x+_=-4. Add 7 and 4 to each side to get (x+7) and (x+4).  You want to FOIL these next, so (x+7)(x+4) = x^2+4x+7x+28.  Now you just need to combine like terms, and BAM.  There's your answer.

You should get something like x^2+11x+28 (:

6xy and -16xy000000000