Question 116538
Use the quadratic formula to solve the equation.
2x^2+ 12x =-5
:
Put the equation in the ax^2 + bx + c = 0 form, add 5 to both sides:
2x^2 + 12x + 5 = 0
:
In this equation a = 2; b = 12; c = 5
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
Substitute:
{{{x = (-12 +- sqrt(12^2-4*2*5 ))/(2*2) }}}
:
{{{x = (-12 +- sqrt(144 - 40 ))/(4) }}}
:
{{{x = (-12 +- sqrt(104))/(4) }}}
:
Find the square root of 104:
{{{x = (-12 +- 10.198)/(4) }}}
:
Two solutions
{{{x = (-12 + 10.198)/(4) }}}
{{{x = -1.8/4 }}}
x = -.45
and
{{{x = (-12 - 10.198)/(4) }}}
{{{x = -22.198/4}}}
x = -5.55
:
Learn this procedure by heart and you can do any quadratic equation that it's possible to solve. It would be time well spent.