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Simplificati raportul:x ² -2x-15 totul supra x²-10x+25 simplificat cu x-5 unde x apartine la R/{5}

Răspuns :

(x ² -2x-15 )/( x²-10x+25 ) =

Δ=4+60=64
x₁=(2+√64)/2 =(2+8)/2=10/2=5
x₂=(2-√64)/2 =(2-8)/2=-6/2=-3

=(x+3)(x-5)/( x-5)² =

=(x+3)/( x-5)
(x²-2x-15)/(x²-10x+25)    simplificat cu (x-5)              unde x∈R/{5}

(x²-10x+25)=(x-5)²

(x²-2x-15)=(x²-5x+3x-15)=x(x-5)+3(x-5)=(x+3)(x-5)

deci  (x²-2x-15)/(x²-10x+25)    =(x+3)(x-5)/(x-5)²=(x+3)/(x-5)

(x²-2x-15)/(x²-10x+25) =(x+3)/(x-5)     unde x∈R/{5}