Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
+1 vote
1.0k views
in Binomial theorem by (46.6k points)

If the binomial coefficients of (2r + 4)th and (r –2)th terms in the expansion of (a + bx) 18 are equal, find r.

1 Answer

+1 vote
by (52.7k points)
selected by
 
Best answer

This is possible only when either

2r + 3 = r - 3  .....(1)

or   2r + 3 + r – 3 = 18 .....(2)

From Eq. (1), r = –6 is not possible.

But, from Eq. (2)

r = 6 Hence, r = 6 is the only solution.

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.

...