Determine if the two triangles

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)