What is 13 divided by 10 5/6

What signals you that factoring by grouping is the best method to use when factoring a problem?

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.

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?