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1)Sa se determine numerele reale care verifica expresiile: a) |a|=8 b)|x|= -8 C) |-y|=2 d)|a+3|=1 e)|-x -4|=5 f) |3-6y|=12 g) |(x-2) (4-y)|=0 Multumesc !

Răspuns :

[tex]a).|a|=8 \Rightarrow a=8 ~sau~a=-8 \\ b).|x|=-8 \Rightarrow Nu~are~solutii \\ c).|-y|=2 \Rightarrow -y=2 \Rightarrow y=-2 \\ -y=-2 \Rightarrow y=2 \\ d).|a+3|=1 \\ a+3=1 \Rightarrow a=1-3 \Rightarrow a=-2 \\ a+3=-1 \Rightarrow a=-1-3 \Rightarrow a=-4 \\ e).|-x-4|=5 \Rightarrow |x+4|=5 \\ x+4=5 \Rightarrow x=5-4 \Rightarrow x=1 \\ x+4=-5 \Rightarrow x=-5-4 \Rightarrow x=-9 [/tex]
[tex]\displaystyle f).|3-6y|=12 \\ 3-6y=12 \Rightarrow -6y=12-3 \Rightarrow -6y=9 \Rightarrow y=- \frac{9}{6} \Rightarrow y=- \frac{3}{2} \\ 3-6y=-12 \Rightarrow -6y=-12-3 \Rightarrow -6y=-15 \Rightarrow y= \frac{15}{6} \Rightarrow y= \frac{5}{2} \\ g). |(x-2)(4-y)|=0 \\ (x-2)(4-y)=0 \\ x-2=0 \Rightarrow x=0+2 \Rightarrow x=2 \\ 4-y=0 \Rightarrow -y=0-4 \Rightarrow -y=-4 \Rightarrow y=4 [/tex]