Mrs. Green needs to store 21 math books on a shelf during school vacation. Each math book is 2.4 centimeters thick. If Mrs. Green stacks the math books on top of each other, how tall does the shelf have to be?

Select all the correct answers.natalie buys a new car. in the first month, the odometer on the car records 800 miles. from past experience, she expects to drive 900 miles per monthselect all the functions that can be used to find the number of miles, f(n), recorded on the odometer after n months.of(n) = 800n + 100f(n) = 9001 - 100f(n) = 900n + 800(1) = 800; }(n) = f(n - 1) + 900, for n > 2f(1) = 800; 1(n) = f(n − 1) + 100, for n > 2(1) = 900; }(n) = f(n - 1) + 800, for n > 2

How many days was the temperature above 90 degrees?

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?