Odpowiedź:
4x kwadrat - 20x + 25 = 0
a = 4 b = -20 c = 25
delta = -20 kwadrat - 4 * 4 * 25
delta = 400 - 400
delta = 0
x0 = -b/2a
x0 = 20/2*4
x0 = 20/8
x0 = 5/2
x0 = 2 1/2
