Help please

Which ordered pair (c, d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

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?

Aline has a slope of . which ordered pairs could be points on a parallel line? check all that apply. (-8, 8) and (2, 2) (-5, -1) and (0, 2) (-3, 6) and (6, -9) (-2, 1) and (3,-2) (0, 2) and (5,5)