What is the product of the expression? -7(-3)

This needs to be done quick you are studying different function tools and begin working with this function y=-160-9(x) use the equation to answer the question y=-160-9(x) what is the y value when x equals -13? y=-160-9(x)

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).

Evaluate-27 ^4/3/8 a) - 81/16 b) 81/16 c) 16/81