已知(7x-13)(5x-4)+(7x-13)(11x-5)

(7x-13)(5x-4)+(7x-13)(11x-5)
=(7x-13)[(5x-4)+(11x-5)]
=(7x-13)(5x-4+11x-5)
=(7x-13)(16x-9)
再问： 题目重新打了
再答： (7x-13)(5x-4)+(7x-13)(11x-5) =(7x-13)[(5x-4)+(11x-5)] =(7x-13)(5x-4+11x-5) =(7x-13)(16x-9) (7x-13)(16x-9) =(ax+b)(16x+c) a=7 b=-13 c=-9 a+b+c =7-13-9 =-15