4x² - 5x + 1 = 0
a = 4; b = - 5, c = 1
Δ = b² - 4.a.c
Δ = (-5)² - 4.4.1
Δ = 25 - 16
Δ = 9
x = - b ± √Δ / 2.a
[tex]x = \frac{-5\± \sqrt{9} }{2*4} [/tex]
[tex]x = \frac{-5\±3}{8} [/tex]
[tex]x' = \frac{-5-3}{8} = \frac{-8}{8} = -1[/tex]
[tex]x' = \frac{-5+3}{8} = \frac{-2}{8} (\div2) = \frac{-1}{4}[/tex]
A. Two real solutions (x' = -1 and x'' = -1/4)
