Question

If the coefficient of the rth and (2r + 5) th terms of the expansion of (1 + x)^ 15 are equal, r =

Answer 1

co·ef·fi·cient [k i físh'nt]
(plural co·ef·fi·cients)
noun
1. numerical part of algebraic term: the number placed before a letter that represents a variable in algebra, e.g. the "3" of "3x" in the equation "3x = 6"
2. figure measuring property of substance: a numerical constant that is a measure of a property of a substance

Answer 2

use binomial expansion general formula

Answer 3

where n=15, r=r, a=1,b=x