Without computing, how do you know that the answer to 7 − (−15) is positive?

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).

The measure of an angle is 117°. what is the measure of a supplementary angle?

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.