Question

Find the domain of the function f(x) = 5x2 + 9x - 8

Answer 1

Answer: Set of all real numbers

As an inequality, the domain is
`-\infty < \text{x} < \infty` to represent x being between negative infinity and positive infinity.

That shortens down to the interval notation
`(-\infty, \infty)`

The reason why the domain is "all real numbers" is because we don't have any issues like division by zero errors, or we don't have negative values under a square root. Replace x with any real number to get some output for f(x).

Visually the graph is a parabola the stretches infinitely to the left and right to confirm the correct domain.