Question

What is the domain of f in the equation
F(x)=5/x2-18x+45

Answer 1

$f(x)=\dfrac{5}{x^2-18x+45}\\\\The\ domain:\\\\x^2-18x+45\neq0\\\\x^2-15x-3x+45\neq0\\\\x(x-15)-3(x-15)\neq0\\\\(x-15)(x-3)\neq0\iff x-15\neq0\ \wedge\ x-3\neq0\\\\\boxed{x\neq15\ \wedge\ x\neq3}\to\boxed{x\in\mathbb{R}-\{3,\ 15\}}$