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1.Efectuati adunarile si scaderile de numere rationale:
a)2supra5+3supra5+1supra5
b)8supra7-9supra7+1supra7
c)1supra2+1supra4+1supra8+1supra16
d)6supra16+3supra8-5supra24-6supra32
e)2supra20+1supra18-1supra16-5supra36
f)6supra12+9supra24-3supra18
2.Calculati:
a)21,2+1,56-20,4;
b)-1,3-15,64+4,8;
c)1,5-2,(3)-0,(6);
d)0,(3)-2,5+7supra6;
e)4-1,(3)+1supra6;
f)-1,(3)-16supra3+6,(6).
3.Aflati termenul necunoscut x din adunarile sau scaderile urmatoare:
a) x-3supra4=4;
b)3supra4+x=72supra11;
c)0,375-x=5;
d)0,58=1-x.
va rog frumos sa ma ajutati!


Răspuns :

Spidie
a)2/5+3/5+1/5=6/5
b)8/7-9/7+1/7=0
c)1/2+1/4+1/8+1/16=8/16+4/16+2/16+1/16=15/16
d)6/16+3/8-5/24-6/32=72/192+72/192-40/192-36/192=68/192=17/48
e)2/20+1/18-1/16-5/36=72/720+40/720-45/720-100/720= -33/720
f)6/12+9/24-3/18=36/72+27/72-12/72=51/72


a)21,2+1,56-20,4=2,36
b)-1,3-15,64+4,8= -12,14
c)1,5-2,(3)-0,(6)=15/10-21/9-6/9=15/10-27/9=5/2-3=5/2-6/2= -1/2
d)0,(3)-2,5+7/6=3/9-25/10+7/6=1/3-5/2+7/6=2/6-15/6+7/6=6/6= -1
e)4-1,(3)+1/6=4-12/9+1/6=4-4/3+1/6=24/6-8/6+1/6=17/6
f)-1,(3)-16/3+6,(6)= - 12/9-16/3+60/9= -12/9-32/9+60/9=16/9


a) x-3/4=4
4x-3=12
4x=15
x=15/4

b)3/4+x=72/11;
33+44x=288
44x=288-33
44x=255
x=255/44

c)0,375-x=5;
375/100-x=5
15/4-x=5
15-4x=20
-4x=20-15
-4x=5
x= -5/4

d)0,58=1-x.
58/100=1-x
58=100-100x
100x=100-58
100x=42
x=42/100
x=21/50