26
a=√( √3-1)²=|√3-1|=√3-1
b= √(√3+1)²=√3+1
ab= (√3-1)*(√3+1)=3-1=2∈n
27
x²+6x+25 miunim
x2+6x+9+16 minim
(x+3)²+16 minim
(x+3)²minim =0 pt ca (orice numar)²≥0
deci (x+3)²+16 minim=0+16=16
si √16=4
analog
2y²+8y+24= 2(y²+4y+12)=2(y²+4y+4+8)= 2[(y+2)²+8] care va avea un minim
de 2(0+8)=16
si √16=4
deci toata expresia va avea un minim de 4+4=8
