How to get 24 with 7 8 5 and 9

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).

Determine the standard form of the equation of the line that passes through (-2,0) and (8,-5)

Determine the intercepts of the line that passes through the following points. (15,-3)(15,−3) (20,-5)(20,−5) (25,-7)(25,−7)