Question

How do you find the domain of the function `f(x)= (2x+3)/(x^2+9x+20)`?

Answer 1

Any value that makes the denominator `=0` is forbidden

So we need to know when `x^2+9x+20=0`

If we factorise we get:
`(x+4)(x+5)=0->x=-4orx=-5`

So these are not allowed. Any other `x`-value is.

Answer : `x!=-4andx!=-5`