We may be given the curve

and
asked to find the set of values of

for
which

We can start by sketching the curve and obtain:
We can just read the solutions off here:

or

We
could have factorised the
expression for

to
obtain

and
solved

to
obtain

hence
the set of values of

For the quadratic above, since the coefficient of

is
1 which is positive, we know it will be a “bum” curve,so the set
of solutions for

will
come in two parts,

or
The curve shown above is

We
are asked for example to find the set of values of

for
which

We
can see from the graph that there is only one set of values:

We
could have factorised the expression for

to
obtain

and
solved

to
obtain

hence
we could write down the set of values of
The curve shown is

We
are asked
to solve

The
curve is a “breast” curve and we can read off the solutions

or

We can also factorise the expression for

to
obtain

and
solve

hence
finding the set of solutions just given.