6.Factorise using suitable identities. a. p² – 12 p – 85 b. 49a² - 84ab + 36b² 

Asked by alphin.jacob | 6th Jan, 2016, 10:41: PM

Expert Answer:

begin mathsize 14px style p squared minus 12 p minus 85 equals p squared minus 17 p plus 5 p minus 85 equals p left parenthesis p minus 17 right parenthesis plus 5 left parenthesis p minus 17 right parenthesis equals left parenthesis p plus 5 right parenthesis left parenthesis p minus 17 right parenthesis  49 a squared minus 84 a b plus 36 b squared equals 49 a squared minus 42 a b minus 42 a b plus 36 b squared equals 7 a left parenthesis 7 a minus 6 b right parenthesis minus 6 b left parenthesis 7 a minus 6 b right parenthesis equals left parenthesis 7 a minus 6 b right parenthesis left parenthesis 7 a minus 6 b right parenthesis equals left parenthesis 7 a minus 6 b right parenthesis squared end style

Answered by Rashmi Khot | 7th Jan, 2016, 11:07: AM