Hellp
answer all 3 i´ll give Brrainliest!!!

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

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.

The lengths of all sides of a triangle are integers when measured in decimeters. one of the sides has length of 1 dm and another of 3 dm. find the perimeter of the triangle.'