Question

va rog repede
Toate exercitiile
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Answer 1

Răspuns:

R

Explicație pas cu pas:

1.a) ⁵3/5=15/25

b) 48/90=24×2/45×2=24/45

2.a) 7/6-(³1/4+⁴1/3-⁶1/2)=7/6-(3+4-6)/12=

²7/6-1/12=(14-1)/12=13/12

b) 2 3/5-(3 1/10-2 1/2+1)=

13/5-(31/10-⁵5/2+¹⁰1)=13/5-(31-25+10)/10=

16/10=8/5

3.a)9/(2n+1)>1

2n+1<9

2n<8

n<4 n=0;1;2;3

b) 3/(2n+1) număr natural

2n+1=±3

2n+1=3

2n=2. n1=1

2n+1=-3

2n=-4

n2=-2 nu spune că și n este natural

4.(abc+bca+cab)/(aaa+bbb+ccc)=

100a+10b+c+100b+10c+a+100c+10a+b)/

(111a+111b+111c)=(111a+111b-111c)/(111a+111b+111c)=1

5.a)[(2/3)²-1/12]:1 4/9-(1/2)³=

(⁴4/9-³1/12):13/9-1/8=(16-3)/12×9/13-1/8=

13/12×9/13-1/8=9/12-2/8=²3/4-1/8=(6-1)/8=

5/8

b)[(2 1/3:3 1/2+5/9)-5/6]:2 1/3+5/6=

[(7/3:7/2+5/9)-5/6]:7/3+5/6=

[(7/3×2/7+5/9)-5/6]×3/7+5/6=

[(³2/3+5/9)-5/6]×3/7+5/6=

[(6+5)/9-5/9]×3/7+5/6=

(11/9-5/9)×3/7+5/6=

6/9×3/7+5/6=2/7+5/6=(12+35)/42=

47/42