When you add two polynomials do you get a polynomial

You purchased 8 pounds 10 ounces of candy from a candy shop. you want to split it equally among 3 classrooms at a local school.

20 solve 2(4 x + 3) < 5 x + 21. a) { x | x < 9} b) { x | x > -5} c) { x | x > -9} d) { x | x < 5}

If f(x) = 3x2 - 2x+4 and g(x) = 5x + 6x - 8, find (f-g)(x).