se foloseste relatia lui Viete:X²-SX+P=0
a)S=4, P=-2
x²-4x-2=0
Δ=16+8=24
X1=(4-√24)/2=(4-2√2)/2=2(2-√2)2 simplificam
X1=2-√2
X2=2+√2
b)S=3, P=2
x²-3x+2=0
Δ=9-8=1
X1=3-1)/2=2/2=1
X2=3+1/2=4/2=2
c) S=-1, P=-7
x²-x-7=0
Δ=1+28=29
X1=(1-√29)/2
X2=(1+√29)/2
d) S=-2, P=8
x²+2x+8=0
Δ=4-32=-28
X1=(-2+28i)/2=2(14i-1)/2=14i-1
X2=-1-14i
