Question

Ex1: Descompuneti in factori ireductibili expresia:x²(x²-10)+9
Ex2:Determinati media geometrica a numerelor x si y care indeplinesc conditia:x²+4y²-4(x+3y)+13=0

Answer 1

notezi a=x^2

a(a-10)+9=a^2-10a+9=a^2-9a-a+9=a(a-1)-9(a-1)=(a-1)(a-9);inlocuiesti si ai (x^2-1)(x^2-9)=(x-1)(x+1)(x-3)(x+3)

x^+4y^2-4x-12y+13=(x-2)patrat+(2y-3)patrat=0

x=2

y=3/2

Mg=radical 2*3/2=radical3