28x^2+84x+7=0

Solution for 28x^2+84x+7=0 equation:

28x^2+84x+7=0

a = 28; b = 84; c = +7;
Δ = b2-4ac
Δ = 842-4·28·7
Δ = 6272
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:

$\sqrt{\Delta}=\sqrt{6272}=\sqrt{3136*2}=\sqrt{3136}*\sqrt{2}=56\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(84)-56\sqrt{2}}{2*28}=\frac{-84-56\sqrt{2}}{56}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(84)+56\sqrt{2}}{2*28}=\frac{-84+56\sqrt{2}}{56}
$