3x2-2x-21=0

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Solution for 3x2-2x-21=0 equation:



3x^2-2x-21=0
a = 3; b = -2; c = -21;
Δ = b2-4ac
Δ = -22-4·3·(-21)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-16}{2*3}=\frac{-14}{6} =-2+1/3 $
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+16}{2*3}=\frac{18}{6} =3 $

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