How many solutions are there?

I've never been good at math he told he loves but he keeps cheating on me, so it ain't adding up sis

Plzzz i beg u so much asaaaap ! what is the slope of this line? enter your answer in the box.

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.