If r1
and
r2
are the roots of
ax2 + bx + c = 0,
show that
r1r2 =
c
a
.
If
r1
and
r2
are roots of
ax2 + bx + c = 0,
then their values are
r1 =
−b +

b2 − 4ac
2a
and
r2 =
−b −

b2 − 4ac
2a
r1r2
=

+

b2 − 4ac
2a

·

−b −

b2 − 4ac
2a

=

+

b2 − 4ac

·

−b −

b2 − 4ac

4a2
=

2

−

b2 − 4ac
2

4a2
=

− (b2 − 4ac)
4a2

=

4a2

=

c
a