Question

What is the coefficient of x4y4 in the expansion of (x + y)8?

Answer 1

70

Explanation:

apex

Answer 2

70

Explanation:

If you use Pascal's Triangle, you will need 9 lines, since there are 9 terms in a binomial raised to the 8th power. Those 9 terms are:

1, 8, 28, 56, 70, 56, 28, 8, 1

The first expansion through the one we need are below (I hope you know how to use Pascal's Triangle!):

`1(x^8)(y^0)+8(x^7)(y^1)+28(x^6)(y^2)+56(x^5)(y^3)+70(x^4)(y^4)+...`