2x^2+2x+7x-21=0

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Solution for 2x^2+2x+7x-21=0 equation:



2x^2+2x+7x-21=0
We add all the numbers together, and all the variables
2x^2+9x-21=0
a = 2; b = 9; c = -21;
Δ = b2-4ac
Δ = 92-4·2·(-21)
Δ = 249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-\sqrt{249}}{2*2}=\frac{-9-\sqrt{249}}{4} $
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+\sqrt{249}}{2*2}=\frac{-9+\sqrt{249}}{4} $

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