Răspuns:
1.
(3-√3)²+(3+√3)²=9-6√3+3+9+6√3+3=24 care este un numar natural
2.
f(x)=x²-4x+2≥-2
x²-4x+2+2≥0
x²-4x+4≥0
Δ=16-16=0 rezulta ca f(x)≥-2
4.
f(x)=-x²-3x+4
f(x) intersecteaza ox
f(x)=0
-x²-3x+4=0
Δ=9+16=25
√Δ=5
x1=(3+5)/-2=-4 ----> A(-4,0)
x2=(3-5)/-2=1 ------>B(1,0)
f(x) intersecteaza oy
f(0)=4 ------> C(0,4)
