In mr. garcias 7th grade math class 4/5 of the students brought a pencil to class. if 6 people did not have pencils, how many students are in her class. use a model

For the function, f(x) = -5x 2, find f(-4).

What is the value of x? enter your answer in the box. (cm)

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.