There are 30 students in mr. thomas' class. if he wants 20% of the students in each group, how many students will be in. each group?

What are the solutions to the equation 4x2+3x=24-x

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.

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)