👤

Rezolvati in R ecuatia a)√x=x-2, b)√x=6-x c)x+√x+1=0

Răspuns :

a)√x=x-2  l²
     x=x²-4x+4 sau x²-5x+4=0
Δ=25-16=9
√Δ=3
x₁=(5-3)/2=1
x₂=(5+3)/2=4

b)√x=6-x  l²
     x=36-12x+x² sau x²-13x+36=0
Δ=169-4·36=25
√Δ=5
x₁=(13-5)/2=4
x₂=(13+5)/2=9

c)x+1=-√x  l²
   x²+2x+1=x sau x²+x+1=0
Δ=1-4=-3 =>ecuatia nu are solutii reale