Wednesday, November 19, 2014

How do I solve the equation 5x^2=8x+2 using the quadratic formula?

To solve an equation means to determine it's roots. Since
it is a quadratic equation, it will have 2 roots.


The
quadratic formula is used to determine the roots:


x1 =
[-b+sqrt(delta)]/2a and x2 =
[-b-sqrt(delta)]/2a


discriminant = delta = b^2 -
4ac


We'll identify the coefficient of the quadratic:
a,b,c.


a = 5, b = -8 and c =
-2


delta = (-8)^2 -
4*5*(-2)


delta = 64 + 40


delta
= 104


We'll take square root both
sides:


sqrt delta = sqrt
104


sqrt delta = 2sqrt 26


x1 =
(8 + 2sqrt 26)/2*5


x1 = (4 +
sqrt26)/5


x2 = (4 -
sqrt26)/5


The roots of the quadratic are: x1
= (4 + sqrt26)/5 and x2 = (4 - sqrt26)/5.

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