Icould really really use some . if someone could me answer like 5 questions like this id appreciate

find m abc

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 product? a-3/15a × 5/a-3

Simplify 1 divided by 2/3 x (-3) divided by 1/6 x (-10)