Question

DAU CORONA AM NEVOIE URGENT DE 18-21 VĂ ROG MULTT :((

Answer 1

$20) \\ \\ a)\frac{3}{4} + \frac{1}{4} = \frac{3 + 1}{4} = \frac{4}{4} = 1 \\ \\ b)2 \frac{1}{2} - \frac{2}{3} = \frac{5 \times 3}{2 \times 3} - \frac{2 \times 2}{3 \times 2} = \frac{15}{6} - \frac{4}{6} = \frac{15 - 4}{6} = \frac{11}{6} = 1 \frac{5}{6} \\ \\ c)\frac{4}{5} \times \frac{5}{7} = \frac{4 \times 5}{5 \times 7} = \frac{20}{35} = \frac{4}{7} \\ \\ d)\frac{3}{4} \times 6 = \frac{18}{4} = \frac{9}{2} = 4 \frac{1}{2} \\ \\ e)\frac{16}{5} : \frac{8}{3} = \frac{16}{5} \times \frac{3}{8} = \frac{16 \times 3}{5 \times 8} = \frac{48}{40} = \frac{6}{5} \\ \\ f)\frac{56}{9} : 0,(7) = \frac{56}{9} \times \frac{10}{7} = \frac{56 \times 10}{9 \times 7} = \frac{560}{63} = \frac{80}{9} = 8 \frac{8}{9} \\ \\ g)( \frac{6}{7}) ^{2} = \frac{ {6}^{2} }{ {7}^{2} } = \frac{36}{49} \\ \\ h)( \frac{4}{5} + 1 \frac{1}{2} - \frac{1}{10}) \times 100 = ( \frac{7}{10} + 1 \frac{1}{2}) \times 100 = 1 + \frac{7}{10} + \frac{1 \times 5}{2 \times 5} = 1 + \frac{7}{10} + \frac{5}{10} = 1 + \frac{7 + 5}{10} = 1 + \frac{12}{10} = 1 + 1 \frac{2}{10} = 2 \frac{2}{10} \times 100 = 2 \frac{1}{5} \times 100 = \frac{11}{5} \times 100 = \frac{1100}{5} = 220$

21)

a)x-0,08=5

x=5+0,08=5,08

b)x:100=8,09

x=8,09•100=809

c)6x-7=233

6x=233+7=240

$x = \frac{240}{6} = 40$

$d)(x + 66) \times \frac{1}{100} = 2 \\ \\ \frac{x + 66}{100} = 2 \\ \\ x + 66 = 2 \times 100 = 200 \\ \\ x = 200 - 66 = 134$