Question : If $(2 x+3 y+4)(2 x+3 y-5)$ is equivalent to $\left(a x^2+b y^2+2 h x y+2 g x+2 f y+c\right)$, then what is the value of $\frac{g + f - c}{abh}$?

Question : If $\frac{x}{y}+\frac{y}{x}=1$ and $x+y=2$, then the value of $x^3+y^3$ is:

Question : If $x+y+z=19, x y z=216$ and $x y+y z+z x=114$, then the value of $x^3+y^3+z^3+x y z$ is:

Question : If $x^4+x^2 y^2+y^4=133$ and $x^2-x y+y^2=7$, then what is the value of $xy$?

Question : If $\frac{x}{4 y}=\frac{3}{4}$ then, the value of $\frac{2 x+3 y}{x–2 y}$ is: