fie ecuatia:
Va rog ajutor... am atasat poza dau coronita!

Răspuns:
[tex]x^{2} -5x+4=0\\\\[/tex]
Δ=b²-4ac
a=1
b=-5
c=4
Δ=(-5)²-4*1*4
Δ=25-16
Δ=9
√Δ=3
x1,2=(-b±√Δ)/2a
x1=5-3/2=2/2=1
x2=5+3/2=8/2=4
a) 1/x1+1/x2=1/2+1/4=(2+1)/4=3/4
b)x1²+x2²=2²+4²=4+16=20