Which of the following shows that polynomials are closed under addition when two polynomials 4x2 − 8x − 7 and −5x + 16 are added?
a. 4x^2 - 13x + 9 may or may not be a polynomial
b. 4x^2 + 13x -23 may or may not be a polynomial
c. 4x^2 -13x + 9 will be a polynomial
d. 4x^2 + 13x - 23 will be a polynomial

∆red ≅ ∆ by rule will give brainiest if possible

98 point question what is the record for most points in one

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?