What is the value of x in the equation 2x - 12 / -3 = 7

I'm so close to finishing all these.

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).

Flashback to semester a. are triangles pqr and stu congruent? what is the congruency that proves they are congruent? what is the perimeter of triangle pqr? show your work.