For vertical strips :

$\displaystyle

M(y-axis)=\int_a^bx\rho[f(x)-g(x)] dx

$

$\displaystyle M(x-axis)=\frac{1}{2}\rho\int_a^b[f(x)+g(x)][f(x)-g(x)]dx$

For Horizontal strips :

$\displaystyle

M(y-axis)=\frac{1}{2}\rho\int_a^b[f(y)+g(y)][f(y)-g(y)]dy$

$\displaystyle M(x-axis)=\int_a^bx\rho[f(y)-g(y)]dy$

Guys l would like to know if these are the correct formulas in this different circumstances. I am not quite sure.