Question 73614
{{{(2x-y)^2}}}Yes you would use the foil method
{{{(2x-y)(2x-y)}}}It can be written as this
{{{2x*2x-y*2x-y*2x+(-y)(-y))}}}When you foil, you multiply every term. So 2x gets multiplied by 2x and -y. Also -y multiplies by 2x and -y. 
{{{4x^2-4xy+y^2)}}}Add like terms. This is the foiled product.