Question

determina nr. nat. x care verifica egalitatea x la puterea a 2+x-1 supra 25=cu 11 supra 5

Answer 1

$\it \dfrac{x^2+x-1}{25}=\dfrac{^{5)}11}{\ 5} \Rightarrow \dfrac{x^2+x-1}{25}=\dfrac{55}{25} \Rightarrow x^2+x-1=55|_{+1} \Rightarrow \\ \\ \\ \Rightarrow x^2+x= 56 \Rightarrow x(x+1)=56 \Rightarrow x(x+1)=7\cdot8 \Rightarrow x=7$

Answer 2

Răspuns

(x²+x-1)\25=11\5 ; x²+x-1=55 ;x²+x-56=0 ;x²+8x-7x-56=x(x+8)-7(x+8)=(x+8)(x-7)=0  ;X-7=0 ;X=7

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