How do you expand #(2x-y)^5# using Pascal’s Triangle?

1 Answer
Jan 12, 2016

#32x^5 -80x^4y +80x^3y^2 -40x^2y^3 +10xy^4 -y^5#

Explanation:

For n=5, the binomial expansion of #(a+b)^5# given in the 6th row of Pascal triangle is #a^5 +5a^4b +10a^3b^2+10a^2b^3+5ab^4 +b^5#. Now to expand the given binomial, plug in a=2x, b=-y to get the desired value. It would be #32x^5 -80x^4y +80x^3y^2 -40x^2y^3 +10xy^4 -y^5#