How do you expand (m+n)^5(m+n)5?

1 Answer
Dec 7, 2016

1m^5+5m^4n+10m^3n^2+10m^2n^3+5mn^4+1n^51m5+5m4n+10m3n2+10m2n3+5mn4+1n5

Explanation:

If you know the 5th row of Pascal's Triangle: 1, 5, 10, 10, 5, 1,
those are the coefficients of each term.

Start the powers of "m" at the highest, 5, and work your way down.
Repeat with powers of "n" from the opposite end.
1m^5+5m^4n+10m^3n^2+10m^2n^3+5mn^4+1n^51m5+5m4n+10m3n2+10m2n3+5mn4+1n5

Notice that each term has powers of "m" and "n" that add up to 5!