Are the following sets vector spaces with the indicated operations? if not ,why not?

1) the set v of non negative real numbers, ordinary addition and scalar multiplication.
2) the set of all polynomials of degree < =3; operations of p.
3) the set v of all 2x2 matrices of the form [ab][0c]; operations of m22
4) the set v of 2x2 matrices with zero determinant; usual matrix operations

An episode of a television show is 60 minutes long when it originally airs with commercials. on a dvd without commercials, the episode is only 417 minutes long. how many1-minute commercials did the episode include when it originally aired? write and solve an equation to justify your answer.

Which expression is equivalent to7_/x^2 ÷ 5_/y^3? assume y# 0

Jessica and martha each have a bag of cookies with unequal quantities. they have 30 cookies total between the two of them. each of them ate 6 cookies from their bag. the product of the number of cookies left in each bag is not more than 80. how many more cookies will jessica have martha? if x represents the number of cookies jessica started with, complete the statements below. the inequality that describes the relationship between the number of cookies each one of them has is x^2 - x +224 > = 0.jessica has at least cookies more than martha.