Question

determine o valor da expressão 3/4-{2/3-[1/2-(2/3+5/4)]}

Answer 1

3/4-{2/3-[1/2-(2/3+5/4)]}

$\frac{2}{3} + \frac{5}{4} = \frac{8 + 15}{12} = \frac{23}{12}$

3/4-{2/3-[1/2-23/12]}

$\frac{1}{2} - \frac{23}{12} = \frac{6 - 23}{12} = - \frac{17}{12}$

3/4-{2/3-[-17/12]}

$\frac{2}{3} + \frac{17}{12} = \frac{8 + 17}{12} = \frac{25}{12}$

3/4-{25/12}

$\frac{3}{4} - \frac{25}{12} = \frac{9 - 25}{12} = - \frac{16}{12} \\ simplificando \: fica. \\ - \frac{4}{3}$

Espero ter ajudado.