I was doing home work but I am stuck with some questions, here is the question
with subparts
,
Let $A=B=C=\Bbb R$, and let $f:A\to B,g:B\to C$ be defined by $f(a)=a-1$ and $g(b)=b^2$. Find
$\text{(a)}\,\,\,\,(f\circ g)(2)\qquad\qquad\text{(b)}\,\,\,\,(g\circ f)(2)$
$\text{(c)}\,\,\,\,(g\circ f)(x)\qquad\qquad\text{(d)}\,\,\,\,(f\circ g)(x)$
$\text{(e)}\,\,\,\,(f\circ f)(y)\qquad\qquad\,\text{(f)}\,\,\,\,(g\circ g)(y)$
Now I am stuck with what does $(2)$, $(x)$ and $(y)$ mean in these questions? For example, (a) $(f \circ g)(2)$ What is $(2)$ here?
Please help me out.
Thanks