Question 64498
Can you please help me solve using the quadratic equation? 
x^2 + 2x - 24 = 0
:
The equation is in the form ax^2 + bx + c, so in this problem:
a = +1; b = +2; c = -24
:
The quadratic formula:
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
:
Substituting for a, b, & c:
{{{x = (-2 +- sqrt( 2^2-4*1*-24 ))/(2*1) }}}
:
{{{x = (-2 +- sqrt( 4 - (-96) ))/(2) }}}
:
Remember a minus a minus is a plus:
{{{x = (-2 +- sqrt( 4 + 96) )/(2) }}}
:
{{{x = (-2 +- sqrt(100))/(2) }}}
:
{{{x = (-2 +- 10 )/(2) }}}
:
Find two solutions:
{{{x = (-2 + 10 )/(2) }}}
{{{x = (8 )/(2) }}}
x = 4
and:
{{{x = (-2 - 10 )/(2) }}}
{{{x = (-12 )/(2) }}}
x = -6
:
Memorize this procedure, you will use it alot. Print it out if you wish.