Question

Find the coefficient of the indicated term in the expansion of the given power of a binomial. Identify the missing exponents.

(x^7y^2);(x+y)^?

Please show work I need to learn how to do it.

Answer 1

you know that it must be (x+y)^9 to get a ?x^7y^2

so the term is
C(9,7) x^7 y^2
= 36x^7y^2

Observe that the 10th row of Pascal's triangle is
1 9 36 84 126 126 84 36 9 1