Two lines or equations are described in each part. Decide whether each system has one solution, no solution, or infinitely many solutions. Show your work AND explain your reasoning for each of your answers.
(a) Line a has a rate of change of 7.
Line b has a rate of change of -7
(b) 2x + 3y = 5.5
4x + 6y = 11
(c) These two graphed lines:
(d) Line c and line d are parallel.