You can
put this solution on YOUR website!ok, completing the square...
. First ignore the 7. Just think about the
. What i want to do is think of the correct number (not the 7) that needs to be there so that I can factorise the quadratic as
where k is a "nice" number, usually an integer, sometimes a simple fraction, rarely a horrible number.
think about
. This expands to be
, so we look at the coefficient before the x-term, our +6, and we note that this is like the "2k", so k must be 3. The number we therefore require
is +9, so what we need is:
.
That is it done, really. All we have to do now is get this to look like the original,
, as follows:
...note the +9-9 cancel each other out, leaving the -7
Hope this is clear?
And now to answer the question...
or
so x+3 = 4 OR x+3 = -4
so x=1 OR x=-7
jon.
