Réponses

2014-06-19T13:12:34+02:00
Bonjour,
Sachant que |x|=
si x>0 alors x
sinon -x
1) |x|=3
si x>0 alors |x|=x=3 => x=3
sinon |x|=-x=3 => x=-3
Sol={ -3,3}
2)
|x+5|=7
si x+5>0 alors |x+5|=x+5=7 => x=2
sinon |x+5|=-(x+5)=7 => -x=7+5 => -x=12 => x=-12
Sol={-12,2}