Describe the family of lines given. Indicate whether or not it contains every line of that...

Describe the family of lines given. Indicate whether or not it contains every line of that description, and, if not, give all lines with that description that are not included in the family.

(a) {y − 1 = m(x + 3) | m real}

(b) {y = 3x + b | b real}

(c) {x/a − y/3 = 1 | a real, a ≠ 0}