4a^2-14a+8=0

Solution for 4a^2-14a+8=0 equation:

4a^2-14a+8=0

a = 4; b = -14; c = +8;
Δ = b2-4ac
Δ = -142-4·4·8
Δ = 68
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{68}=\sqrt{4*17}=\sqrt{4}*\sqrt{17}=2\sqrt{17}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-2\sqrt{17}}{2*4}=\frac{14-2\sqrt{17}}{8}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+2\sqrt{17}}{2*4}=\frac{14+2\sqrt{17}}{8}
$