Dat kan ook...

$\eqalign{ & x^2 - 5x + 2\frac{3} {4} = 0 \cr & 4x^2 - 20x + 11 = 0 \cr & \left( {2x - 5} \right)^2 - 25 + 11 = 0 \cr & (2x - 5)^2 - 14 = 0 \cr & 2x - 5 = \pm \sqrt {14} \cr & x = 2\frac{1} {2} - \sqrt {14} \vee x = 2\frac{1} {2} + \sqrt {14} \cr}$