21x2+6x-2=0

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Solution for 21x2+6x-2=0 equation:



21x^2+6x-2=0
a = 21; b = 6; c = -2;
Δ = b2-4ac
Δ = 62-4·21·(-2)
Δ = 204
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:
$\sqrt{\Delta}=\sqrt{204}=\sqrt{4*51}=\sqrt{4}*\sqrt{51}=2\sqrt{51}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-2\sqrt{51}}{2*21}=\frac{-6-2\sqrt{51}}{42} $
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+2\sqrt{51}}{2*21}=\frac{-6+2\sqrt{51}}{42} $

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