You have a rack that holds 30 cds you can fit 7 more cd's on the right before the rack is full how many cds are in the rack

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).

Which expressions are equivalent to -6 + 3m

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?