Page 44, question 12, question B 13, the answer is not unique. x？ -1 15 problem (1) Original formula =-401-599-×-401-599-=

(2) The original formula = ﹙15 ﹢ 5 ﹚× ﹙15 ﹚ = 200.

46 pages 15 questions (1) 4-xy? (2) Original formula =[3]A-B(2)A-B? =﹙5a﹣b﹚？

(3) The original formula =4a? ﹢4ab﹢b？ ﹣8ab=4a？ -4ab﹢b？ =﹙2a﹣b﹚？

(4) The original formula = 3a [(x? ﹢4﹚? ﹣ 16x？ ]=3a﹙x﹢2﹚？ ﹙x-2﹚？

Question 16 (1) Original formula = 1/2× (3.7) (2.7)? = 1/2 (2) (original formula = (198) (202)? = 16

Question 17 (X)? ﹢2xy﹚﹢x？ =2x？ ﹢2xy=2x﹙x﹢y﹚

I have been typing for a long time! ! /(ㄒㄒ o)/~ ~ I hope I can help you! Adopt it! ! \(^o^)/