Which of these systems of equations has infinitely many solutions? Explain how you know.
a. y = 3x – 6
y = 3(x - 2)

b. y = 5x +10
y = -5x + 10

c. y = 6x +18
y = 6x - 18

d. y = 3x + 12
y = 3(x + 9)

This stem-and-leaf plot represents the heights of the students on ralph's basketball team. one student's height is missing from the plot. if the mean height of all the students on the team is 61 inches, what is the missing height? a. 55 in. b. 59 in. c. 61 in. d. 65 in.

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

Reduce fractions expressing probability to lowest terms. in 3,000 repetitions of an experiment, a random event occurred in 500 cases. the expected probability of this event is?