Sarthaks Test
+1 vote
244 views
in Mathematics by (15.0k points)

Use a suitable identity to get each of the following products.

(i) (7a − 9b) (7a − 9b)

(ii) (− a + c) (− a + c)

1 Answer

+1 vote
by (24.8k points)
selected by
 
Best answer

(i) (7a − 9b) (7a − 9b) = (7a − 9b)2

= (7a)2 − 2(7a)(9b) + (9b)2 [(a − b)2 = a2 − 2ab + b2]

= 49a2 − 126ab + 81b2

(ii) (− a + c) (− a + c) = (− a + c)2

= (− a)2 + 2(− a) (c) + (c)2 [(a + b)2 = a2 + 2ab + b2]

= a2 − 2ac + c2

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...