Question

Given the function f(x) = X-X-2x, on which intervals is f(x) => 0?

Answer 1

we have the following:

$f\mleft(x\mright)=x-x-2x\rightarrow f(x)=-2x$

now, in which interval is greater than or equal to 0

$f\mleft(x\mright)\ge0$

The interval is:

$(-\infty,0)$