Answer:I will only do Q.11 a. Sequence X_ is going up by 201 b. 8=116 and 13=2361 c. Sequence a_ is down up by 131 d. 12=39 and 15=0Step-by-step explanation:1 a.Sequence X_ is going up by 201 b. go from 566=56 +20=767=76 +20=968= 96+20=1169=116+20=13610=136+20=15611=156+20=17612=196+20=21613=216+20=2361 c. Sequence a_ is down up by 131 d. go from 7810=78-13=6511=65-13=5212=52-13=3913=39-13=2614=26-13=1315=13-13=0