Question

in the expansion of (x+y)^15 a certain term contains x^10. What is the exponent of y in this term?
a.8
b.9
c.11
d.5

Answer 1

in the binomial expansion of:\[(x+y)^{15}\]you know the first term will be \(x^{15}\) and the last term will be \(y^{15}\). every term in between will be of the form:\[Cx^ay^b\]where C is some constant and a+b=15

Answer 2

can you work out the answer now?

Answer 3

no

Answer 4

think about it and re-read what I have written.
remember you are told the term in question has \(x^{10}\) in it. so using my notation you know that a=10 therefore:

a + b = 15
10 + b = 15

therefore b=?

Answer 5

5

Answer 6

correct!

Answer 7

thank you :)

Answer 8

yw :)

Answer 9

ok and i have one more question

Answer 10

just type each question in the list to the left