trebuie sa inveti semnele (+)·(-)=-
(-)·(-)=+ si asa mai departe
1) 3intreg 2/3=(3·3+2)/3=11/3
⇒26/15-11/3-17/5 aducem la acelasi numitor si amplificam
(26-11·5-17·3)/15=(26-55-51)/15=(-29-51)/15=-80/15=-5,(3)
asa se rezolva toate
2) -35/15-19/24+7/3 aducem la acelasi numitor , pt.aceasta calculam c.m.m.m.c
[15,24,3]=
15=3·5
24=2³·3
3=3
[15,24,3]=3·2³·5=120 este numitorul comun si amplificam
⇒(-35·8-19·5+7·40)=(-280-95+280)/120=(-375+280)/120==-95/120=-19/24
3)1 intreg5/6=(1·6+5)/6=11/6
8/3-1/2-11/6=(8·2-1·3-11)/6=(16-3-11)/6=2/6=1/3
4) 2 intreg 3/8=(2·8+3)/8=19/8
19/8-7/2-5/4=(19-7·4-5·2)/8=(19-28-10)/8=(-9-10)/8=-19/8
5) (-2/3)·(-4/5)=(2·4)/3·5=8/15
6) (-7/2)·(-5/9)=35/18
7)2 intreg 2/3=(2·3+2)/3=8/3
5/2·(-9/25)·8/3=(-45/50)·8/3=(-360/150) simplificam=-36/15