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Help dau coroana+10 puncte!!!Descompuneti in factori expresiile:b)x³-9x²-9x+81;c)x²-5x-24....

Răspuns :

b)x³-9x²-9x+81=x²(x-9)-9(x-9)=(x-9)(x²-9)=(x-9)(x-3)(x+3)
c)x²-5x-24=x²-8x+3x-24=x(x-8)+3(x-8)=(x-8)(x+3)


b)x³-9x²-9x+81(folosim metoda gruparii termenilor tot cate doi) =x²(x-9)-9(x-9) =(x-9)(x²+9) ;c)x²-5x-24(aici nu avem formule deci folosim suma si produs)=x²-8x+3x-24=x(x-8)+3(x-8)=(x-8)(x+3)