21-44x+4x^2=0

Solution for 21-44x+4x^2=0 equation:

21-44x+4x^2=0

a = 4; b = -44; c = +21;
Δ = b2-4ac
Δ = -442-4·4·21
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-44)-40}{2*4}=\frac{4}{8}
=1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-44)+40}{2*4}=\frac{84}{8}
=10+1/2
$