Aresearcher posts a print advertisement offering $20 in exchange for participation in a short study. the researcher accepts the first five people who respond to the advertisement. which of the following statements is true about the sample?

it is a valid sample because the first five people were selected to participate.
it is not a valid sample because it is not a random sample of the population.
it is a valid sample because money was offered to participants.
it is not a valid sample because it is only a short study.

Someone answer this asap rn for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =

Graph the equationy=x^2 -[tex]y = x^{2} - 2[/tex]

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.