Question

Explicitati modulul :
l 1- √7 l
l +√3 + √2 l
l8 + √49 l
l (3 - √2) la puterea a doua l

Answer 1

l 1- √7 l  =      - ( 1 - √7 ) = - 1 + √7
numar negativ ↑
l +√3 + √2 l = +( √3 + √2 ) = √3 + √2 
numar pozitiv ↑
l8 + √49 l = I 8 + 7 I = I 16 I = 16 
l (3 - √2) ² l = I 9  - 6√2 + √4 I = I 9 + 2 - 6√2 I = I 11 - 6√2 I = 11 - 6√2
I - √3 - √2 I =  -  ( - √3 - √2 ) = √3 + √2
numar neg.     ↑

Answer 2

$a).|1- \sqrt{7} |= \sqrt{7} -1 \\ b).|- \sqrt{3} - \sqrt{2} |= \sqrt{3} + \sqrt{2} \\ c).|8+ \sqrt{49}|=|8+7|=|15|=15 \\ d).|(3- \sqrt{2} )^2|=|3^2-2 \cdot 3 \cdot \sqrt{2} + \sqrt{2} ^2|=|9-6 \sqrt{2} +2|= \\ =|11-6 \sqrt{2} |=11-6 \sqrt{2}$