What is the binomial expansion of (x+2)^5(x+2)5?

1 Answer
Jul 19, 2015

(x+2)^5 = x^5+10x^4+40x^3+80x^2+80x+32(x+2)5=x5+10x4+40x3+80x2+80x+32

Explanation:

Write out the 66th row of Pascal's triangle as a sequence:

1, 5, 10, 10, 5, 11,5,10,10,5,1

Write out ascending powers of 22 from 2^020 up to 2^525 as a sequence:

1, 2, 4, 8, 16, 321,2,4,8,16,32

Multiply the two sequences together to get:

1, 10, 40, 80, 80, 321,10,40,80,80,32

These are the coefficients of the expansion:

(x+2)^5 = x^5+10x^4+40x^3+80x^2+80x+32(x+2)5=x5+10x4+40x3+80x2+80x+32