\(A=\dfrac{4x^2\left(x+y\right)-9y^2\left(x+y\right)}{4x^2\left(x-y\right)-9y^2\left(x-y\right)}=\dfrac{\left(4x^2-9y^2\right)\left(x+y\right)}{\left(4x^2-9y^2\right)\left(x-y\right)}=\dfrac{x+y}{x-y}\)
Với x=2014, y=14:
\(A=\dfrac{2014+14}{2014-14}=\dfrac{2028}{2000}=\dfrac{507}{500}\)