If 4 watches cost 76.800. Find the cost of 9 watches pls answer my question

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 area of the triangle 10 13 12

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined