Solve the equation: 5x^2 + 13 x +8 =0

Wednesday, October 20, 2010

The quadratic equation 5x^2 + 13x +8 =0 has to be
solved.

The solution of quadratic equation ax^2 + bx + c =
0 is given by the formula $\displaystyle\frac{{-{b}\pm\sqrt{{{{b}}^{{2}}-{4}{a}{c}}}}}{{{2}{a}}}$

For
5x^2 + 13x +8 =0, a = 5, b = 13 and c = 8. Substituting these values in the formula for
the roots gives:

$\displaystyle{\left(-{13}\pm\sqrt{{{{13}}^{{2}}-}}\right.}$
4*5*8))/(2*5)

= $\displaystyle{\left(-{13}\pm\sqrt{{{169}-}}\right.}$
160))/(2*5)

=
$\displaystyle\frac{{-{13}\pm\sqrt{{{9}}}}}{{{2}\cdot{5}}}$

= $\displaystyle\frac{{-{13}-{3}}}{{10}}$ and $\displaystyle{\left(-{13}+\right.}$
3)/10

= -1.6 and -1

The roots
of the equation are -1 and -1.6

Blog