Question 1092049
First simplify,
{{{(x^3y^(-4))(4x^2y)^(-2) =(x^3y^(-4))*((1/16)x^(-4)y(-2))}}}
{{{(x^3y^(-4))(4x^2y)^(-2)=(x^(3-4)y^(-4-2))/16)}}}

{{{(x^3y^(-4))(4x^2y)^(-2)=(x^(-1)y^(-6))/16)}}}
{{{(x^3y^(-4))(4x^2y)^(-2)=1/(16xy^6)}}}
Now substitute,
{{{(x^3y^(-4))(4x^2y)^(-2)=1/(16(1/2)(-1/2)^6)}}}
Now finish it off.