Question

Let f(x)=5/x and g(x)= 2x^2=5x and What two numbers are not in the domain of f o g?

Answer 1

you meant that g(x)= 2x^2-5x, right ?

Answer 2

\[fog=f \left\{ g \left( x \right) \right\}=f \left( 2 x^2-5x \right)=\frac{ 5 }{ 2 x^2-5x }\]
this is not defined when \[2 x^2-5 x=0\]
or x(2x-5)=0
find x