Question

Va rog! Exercițiul 4,5

Answer 1

Exercitiul 4

$\displaystyle{ \frac{4}{3} = \frac{5}{3} - \frac{1}{3} }$

$\displaystyle{ \frac{40}{30} = \frac{60}{30} - \frac{20}{30}}$

$\displaystyle{ \frac{20}{9} = \frac{27}{9} - \frac{7}{9} }$

$\displaystyle{ \frac{8}{6} = \frac{19}{6} - \frac{11}{6} }$

$\displaystyle{ \frac{16}{12} = \frac{20}{12} - \frac{4}{12} }$

Exercitiul 5

$\displaystyle{ \frac{25}{99} - (x + \frac{3}{99}) = \frac{14}{99}}$

$\displaystyle{ (x + \frac{3}{99}) = \frac{25}{99} - \frac{14}{99} }$

$\displaystyle{ x + \frac{3}{99} = \frac{25-14}{99} }$

$\displaystyle{ x + \frac{3}{99} = \frac{11}{99} }$

$\displaystyle{ x = \frac{11}{99} - \frac{3}{99} }$

$\displaystyle{ x = \frac{11-3}{99} }$

$\displaystyle{ x = \frac{8}{99} }$

Exercitiul 6

a = 320

b = 25% din a

$\displaystyle{ b = \frac{25}{100} \cdot a }$

$\displaystyle{ b = \frac{25 \cdot 320}{100} }$

$\displaystyle{ b = \frac{8000}{100} }$

b = 80

a + b = 320 + 80

a + b = 400

c = 75% din a + b

$\displaystyle{ c = \frac{75}{100} \cdot (a + b) }$

$\displaystyle{ c = \frac{75 \cdot 400}{100} }$

$\displaystyle{ c = 75 \cdot 4 }$

c = 300

a + b + c = 400 + 300

a + b + c = 700