Question

Rezolvati va rog ex.19

Answer 1

a) x⁴+2x+1 - 4 = 0 => (x²+1) - 2² = (x²+1-2)(x²+1+2)=(x²-1)(x²+3)=0
     => x²=1 si x²=-3 => x=(+ -) 1 si x = (+ -)√3
b) (x⁴ -2x²+1) +4x⁴-4 = 0 => (x²-1)²+4(x⁴-1)=0
=> (x²-1)(x²-1)+4(x²+1)(x²-1)=0 => (x²-1)(x²+1+4x²+4)=0 => (x-1)(x+1)(5x²+5)=0
=> 5(x+1)(x+1)(x²+1)=0 => x₁= - 1, x₂=1, x₃= i, x₄= -i

Si cam asa si celelalte doua.... Succes!