Question

Exercițiul 2 (tot)...... VĂ ROOOOOG! =)))

Answer 1

$1) \\ \\ ( \frac{7}{4} + \frac{1}{6} \times \frac{12}{23}) = \frac{23}{12} \times \frac{12}{23} = \frac{23 \times 12}{12 \times 23} = \frac{276}{276} = 1 \\ \\ ( \frac{5}{6} - \frac{1}{3}) : \frac{1}{4} = \frac{3}{6} : \frac{1}{4} = \frac{1}{2} : \frac{1}{4} = \frac{1}{2} \times 4 = \frac{4}{2} = 2$

2)

a)3,5x+3,35=20,85

3,5x=20,85-3,35=17,5

$x = \frac{17.5}{3.5} = 5$

b)0,8(x+0,2)=4,96

$x + 0,2 = \frac{4,96}{0,8} = 6,2$

x=6,2-0,2=6

$3) \frac{x + 3}{5} + \frac{x + 5}{6} + \frac{x + 7}{7} = 6 \\ \\ 42(x + 3) + 35(x + 5) + 30(x + 7) = 1260 \\ \\ 42x + 126 + 35x + 175 + 30x + 210 = 1260 \\ \\ 107x + 511 = 1260 \\ \\ 107x = 1260 - 511 = 749 \\ \\ x = \frac{749}{107} = 7$