Question

Se considera numerele x=3+V7 si y=3-V7.Calculati suma lor apoi suma opuselor lor.

Answer 1

$\it x+y=3+\sqrt7+3-\sqrt7=3+3=6\\ \\ -x+(-y)=-3-\sqrt7-3+\sqrt7=-3-3=-6$

Answer 2

Explicație pas cu pas:

$\bf x= 3 + \sqrt{7}$

$\bf y= 3 - \sqrt{7}$

$\bf x + y= (3 + \sqrt{7}) + (3 - \sqrt{7})$

$\bf \purple{x + y}=3 + \sqrt{7}+ 3 - \sqrt{7} = \purple{ \underline{ \: 6 \: }}$

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$\bf (- x) + (- y)= - (3 + \sqrt{7})+ [ - (3 - \sqrt{7})] =$

$\bf \red{ (- x) + (- y)}= - 3 - \sqrt{7}+ (- 3 + \sqrt{7})= - 3 - \sqrt{7}- 3 + \sqrt{7}= \red{\underline{ - 6 }}$