3. Determine a) (-48) div(12)=-4 [ ( 4. ) cdot (2)/(3)+(5)/(3)-(1)/(3)= ( 4) ) cdot (2)/(5)-(3)/(5)+(1)/(5)= ( 4) )((5)/(10)) cdot((3)/(8))= ( d) ) (-(6)/(7)) div((9)/(12))= ]

Vamos corrigir e resolver cada item:<br /><br />a) \( (-48) \div (12) = -4 \)<br /><br />b) \(\frac{2}{3} + \frac{5}{3} - \frac{1}{3} = \frac{2+5-1}{3} = \frac{6}{3} = 2\)<br /><br />c) \(\frac{2}{5} - \frac{3}{5} + \frac{1}{5} = \frac{2-3+1}{5} = \frac{0}{5} = 0\)<br /><br />d) \(\left(-\frac{6}{7}\right) \div \left(\frac{9}{12}\right) = \left(-\frac{6}{7}\right) \times \left(\frac{12}{9}\right) = \left(-\frac{6}{7}\right) \times \left(\frac{4}{3}\right) = -\frac{24}{21} = -\frac{8}{7}\)<br /><br />Portanto, as respostas corretas são:<br /><br />a) -4<br />b) 2<br />c) 0<br />d) -\frac{8}{7}