Can you solve number 7. and could you include steps.

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 the following expression 1/3^2

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much