Arthur D. answered 09/07/18
Tutor
4.9
(274)
Mathematics Tutor With a Master's Degree In Mathematics
prove la/bl=lal/lbl (b≠0 and if a=0 in any case then la/bl=lal/lbl=0)
case 1 a>0, b>0
la/bl=a/b and lal/lbl=a/b
case 2 a<0, b>0
la/bl=-(a/b) and lal/lbl=-(a)/b=-(a/b)
case 3 a>0, b<0
la/bl=-(a/b) and lal/lbl=a/-(b)=-(a/b)
case 4 a<0, b<0
la/bl=a/b and lal/lbl=(-a)/(-b)=a/b