7 and -3 are the roots of the quadratic equation x^2+kx-21=0 what is the value of k

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Which statement accurately explains whether a reflection over the x-axis and a 180° rotation would map figure acb onto itself?

In a probability experiment, karen flipped a coin 76 times. the coin landed on heads 32 times. what percentage of the coin flips resulted in tails? round to the nearest percent. a. 58% b. 65% c. 42% d. 60%