If x/2y=3 then what is the value of x^2-36y^2

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

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.

Which expression gives you the distance between the points (5,1)and(9,-6)