Question

alo
Calculaţi:
a) 5/2 +9/2 – 2/5;
b) 3×7/2 -4/2;
c) 3×4/8 +2×9/2;
d) (3/3 - 6):2 t
e) (12/2 - 11/2): 1/20
f) 5/1(13/2 + 4/3);​

Answer 1

Salut.

Punctul a)

$\displaystyle{ \frac{5}{2}+\frac{9}{2} - \frac{2}{5} = \frac{5 + 9}{2} - \frac{2}{5} }$

$\displaystyle{ =\frac{14}{2}-\frac{2}{5} }$

$\displaystyle{ =7 - \frac{2}{5} = ^{5)}\frac{7}{1}-\frac{2}{5} }$

$\displaystyle{ = \frac{35}{5}-\frac{2}{5}=\frac{35-2}{5} }$

$\boxed{=\frac{33}{5}}$

Punctul b)

$\displaystyle{ 3 \cdot \frac{7}{2}-\frac{4}{2}=\frac{3 \cdot 7}{2} - \frac{4}{2} }$

$\displaystyle{ =\frac{21}{2}-\frac{4}{2}=\frac{21-4}{2} }$

$\boxed{=\frac{17}{2}}$

Punctul c)

$\displaystyle{ 3 \cdot \frac{4}{8} + 2 \cdot \frac{9}{2}=\frac{3 \cdot 4}{8} + \frac{2 \cdot 9}{2} }$

$\displaystyle{ =\frac{12}{8}^{(4}+\frac{18}{2} }$

$\displaystyle{ =\frac{3}{2} + \frac{18}{2} =\frac{3+18}{2} }$

$\boxed{=\frac{21}{2}}$

Punctul d)

$\displaystyle{(\frac{3}{3} - 6) : 2= (1 - 6) : 2 }$

$\displaystyle{ = (-5) : 2 }$

$\boxed{=-2,5}$

Punctul e)

$\displaystyle{ (\frac{12}{2} -\frac{11}{2}) : \frac{1}{20}=\frac{12-11}{2} : \frac{1}{20} }$

$\displaystyle{ =\frac{1}{2} : \frac{1}{20} = \frac{1}{2} \cdot \frac{20}{1} }$

$\displaystyle{ =\frac{20}{2} }$

$\boxed{=10}$

Punctul f)

$\displaystyle{ \frac{5}{1} \cdot (^{3)}\frac{13}{2} + ^{2)}\frac{4}{3}) = 5 \cdot (\frac{39}{6}+\frac{8}{6}) }$

$\displaystyle{ = 5 \cdot \frac{39+8}{6} }$

$\displaystyle{ =5 \cdot \frac{47}{6} }$

$\boxed{=\frac{235}{6}}$

- Lumberjack25