How to factorise 100-(x-5)2 ,means square. Share with your friends Share 1 Brijendra P. answered this 100 - (x-5)2 = 102- (x-5)2 [using a2 - b2 = (a-b)(a+b)] = (10 - x + 5)(10+x-5) =(15-x)(5+x) 5 View Full Answer Abhinav answered this 100 - (x-5)2 = 102- (x-5)2 [using a2 - b2 = (a-b)(a+b)] = (10 - x + 5)(10+x-5) =(5-x)(5+x) is the factorised form -3