Explain why the two equations below have the same solutions.
x + 3y = −1
−2x − 6y = 2
a. the two equations have the same slope, so they have the same solutions.
b. the second equation is a multiple of the first equation, so they have the same solutions.
c. the graphs of the equations are parallel and do not intersect, so any solution of one is a solution of the other.
d. the lines are perpendicular, so they have the same solutions.

Luke started a weight-loss program. the first week, he lost x pounds. the second week, he lost pounds less than times the pounds he lost the first week. the third week, he lost 1 pound more than of the pounds he lost the first week. liam started a weight-loss program when luke did. the first week, he lost 1 pound less than times the pounds luke lost the first week. the second week, he lost 4 pounds less than times the pounds luke lost the first week. the third week, he lost pound more than times the pounds luke lost the first week.