Quick Homework Help

# (x+5y) at cube how you do th ⚑ Flag

by Vanessa087 at November 22, 2009

do you mean (x+5y)^2 ? If so I believe it is X^2+5y^2

Rachel. November 22, 2009

Are you looking for (x+5y) cubed?  (x+5y)^3 = (x + 5y)*(x+5y)*(x+5y)                = (x^2 + 5xy + 5xy + 25y^2)*(x+5y)                = (x^2 +10xy + 25y^2)*(x+5y)                = x^3 + 5(x^2)y + 10(x^2)y + 50xy^2 + 25xy^2 + 125y^3                = x^3 + 15x^2y + 75xy^2 + 125y^3Just remember that when multiplying parentheses with more than one term by another parentheses, all the things in each group, must multiply all the things in the other.  So I just take the first group of things, and one by one I multiply each thing to each thing in the second group.

Alison037 November 22, 2009

Also, please please please don't make the mistake of distributing an exponent to the terms. If you have (x + 5y)^2, make sure you understand that this means (x + 5y)*(x + 5y) = x^2 + 10xy + 25y^2If you want to know more details about this, watch this video, problem 2 or 3:http://www.brightstorm.com/d/math/s/algebra/u/polynomials-2/t/multiplying-monomials-andor-binomials-and-foilor this video:http://www.brightstorm.com/d/math/s/algebra-2/u/polynomials/t/multiplying-polynomials

Alison037 November 22, 2009