Efectuati:a) (1 un intreg -19 supra 20) ori (-5)+13 supra 4;b)2 supra 7-(1-5 supra 7)ori (13 supra 2-3 supra 4);c)2 intregii ori (5 supra -1 supra 3)-(2 supra 7)la puterea 2 14 supra 3;
d)2 ori [5-5 supra 8 ori (1 supra 3-3 supra 5)];e)1 supra 4 :[5 supra 4 -2 supra 3 ori (1,5-0,75)];f)[ 1 intreg(3 supra 5 )la puterea 5:( 3 supra 5)la puterea 4]:5 supra 13.

[tex]\displaystyle (1-\frac{19}{20} )\times (-5)+\frac{13}{4} =(\frac{20}{20} -\frac{19}{20} )\times (-5) +\frac{13}{4} =\frac{1}{\not20} \times (\not-5) +\frac{13}{4} =-\frac{1}{4} +\frac{13}{4} =\frac{12}{4} =3[/tex]

b)

[tex]\displaystyle \frac{2}{7} -(1-\frac{5}{7} )\times (\frac{13}{2} -\frac{3}{4} )=\frac{2}{7} -(\frac{7}{7} -\frac{5}{7} )\times (\frac{26}{4} -\frac{3}{4} )=\frac{2}{7} -\frac{\not2}{7} \times \frac{23}{\not4} =\frac{2}{7} -\frac{23}{14} =\frac{4}{14} -\frac{23}{14} =-\frac{19}{14}[/tex]

c)

[tex]\displaystyle 2 \times (\frac{5}{\frac{-1}{3} } )-(\frac{2}{7} )^2\times\frac{14}{3} =2 \times (-15)-\frac{4}{\not49} \times\frac{\not14}{3} =-30-\frac{8}{21} =-\frac{630}{21} -\frac{8}{21} =-\frac{638}{21}[/tex]

d)

[tex]\displaystyle 2\times [5-\frac{5}{8} \times (\frac{1}{3} -\frac{3}{5} )]=2\times[5-\frac{5}{8} \times (\frac{5}{15} -\frac{9}{15} )]=2\times[5-\frac{5}{8} \times (-\frac{4}{15} )]=2\times (5+\frac{1}{6} )=2\times(\frac{30}{6} -\frac{1}{6} )=\not2\times \frac{29}{\not6} =\frac{29}{3}[/tex]

e)

[tex]\displaystyle \frac{1}{4} :[\frac{5}{4} -\frac{2}{3} \times(1,5 -0,75)]=\frac{1}{4} :[\frac{5}{4} -\frac{2}{3} \times0,75]=\frac{1}{4} :[\frac{5}{4} -\frac{2}{3} \times\frac{\not75}{\not100} ]=\frac{1}{4} :[\frac{5}{4} -\frac{2}{\not3} \times \frac{\not3}{4} ]=\frac{1}{4} :[\frac{5}{4} -\frac{2}{4} ]=\frac{1}{4} :\frac{3}{4} =\frac{1}{\not4} \times \frac{\not4}{3} =\frac{1}{3}[/tex]

f)

[tex]\displaystyle [1(\frac{3}{5} )^2:(\frac{3}{5} )^4]:\frac{5}{13} =[1\frac{9}{25} :\frac{81}{625} ]\times\frac{13}{5} =\frac{34}{25} \times\frac{\not625}{81} \times\frac{13}{\not5} =\frac{34}{\not25} \times\frac{\not125}{81} \times 13=34\times\frac{5}{81} \times 13=\frac{2210}{81}[/tex]