Question

Algebra 2

If f(x) = x2 – 1 and g(x) = 2x – 3, what is the domain of
f(g(x))

(-infinity,Infinity)
(-1, Infinity)
(-5, Infinity)
(Infinity, -Infinity)

Answer 1

Do you know how to do f(g(x))?

Answer 2

yes

Answer 3

What do you get?

Answer 4

(2x-3)^2 - 1 right?

Answer 5

yes

Answer 6

So what do i do next?

Answer 7

The answer is all real numbers

Answer 8

( - infinity, infinity )

Answer 9

Howcome? thats what i dont understand

Answer 10

but ty

Answer 11

The answer will always be real numbers, since it is not a fraction

Answer 12

linear equations in form of y= mx + b or ax^2+bx+c will always have real number for its domain

Answer 13

if you simplify your equation more, it is a quadratic equation

Answer 14

oh i get it now

Answer 15

The only time you have to find the domain specifically is, if the equation is a rational function or fraction form

Answer 16

There are many other cases/rules too.

Answer 17

This won't apply for square roots, or natural log functions

Answer 18

But, just to remember, if the equation is in linear form or quadratic form, the answer is always ( - infinity, infinity ) (when both are not rational functions / fractions ).