Question

Perform the indicated operation and state the domain. Let f(x)=x-1 and g(x)=x+1

f(x) - g(x)

Heres my work
(x-1) - (x+1)
x-x=0 and -1-1=-2
Answer =-2 because the x's cancel each other out.
How do i find the domain when there is no x in the answer?

Answer 1

The domain of a constant (-2) is ℝ.

The other way to figure it out is
the domain of f(x) is ℝ
the domain of g(x) is ℝ
From the closure property of subtraction of real numbers, the domain of f(x)-g(x) is also ℝ.

Answer 2

Thanks. What does that symbol mean? and how do i write it?

Answer 3

The symbol means all real numbers, or all numbers between -∞ to +∞ (negative infinity to positive infinity).

It is written as a capital R, with a double stroke on the first.

Answer 4

OK THANKS!

Answer 5

You're welcome!