Question

j)determine the interval for the domain

1. $f(x)=x^{2}+6x - 1$
2. $f(x)=-x^{2}-8x + 5$
3. $f(x)=2(x + 5)^{2}+7$
4. $f(x)=3(-2x + 1)^{2}-7$

Explanation:

Step1: Recall domain definition

The domain of a polynomial function is the set of all real numbers.

Step2: Analyze each function

All given functions $f(x)=x^{2}+6x - 1$, $f(x)=-x^{2}-8x + 5$, $f(x)=2(x + 5)^{2}+7$, $f(x)=3(-2x + 1)^{2}-7$ are polynomial functions (quadratic in form).

Answer:

$(-\infty,\infty)$ for all functions 1 - 4.