# If f(x) = x^2-1 and g(x)=1-x, how do you find f(g(x))?

You just substitute the $g \left(x\right)$ function into the $f \left(x\right)$
$f \left(g \left(x\right)\right) = f \left(1 - x\right)$
$= {\left(1 - x\right)}^{2} - 1$
$= \left(1 - 2 x + {x}^{2}\right) - 1$
$= {x}^{2} - 2 x \mathmr{and} x \left(x - 2\right)$