The equation
has roots
and
, and the equation
has roots
and
. find the value of
and of
.
We need to know two things about a quadratic equation of the
form
1.
the sum of the two roots with the sign changed.
2.
the product of the two roots.
We use 1 and 2 on the first equation:
Since
has roots
and
,
Using 1,
multiplying both sides by
Using 2,
Now we use 1 and 2 on the second equations:
Since
has roots
and
.
Using 1,
multiplying both sides by
getting the LCD of
Combine numerators over the LCD:
Factor out
on top:
Now,
since we have above that
,
and since
, we can replace
by
,
and
since we have above that
,
we can replace
by -2,
Multiply both sides by
Divide both sides by
So the value of
is
-----------------
Using 2 on the second equation,
But since
,
Now since from above, we have
,
becomes
So the value of
is
Edwin