Question

Calcule as frações a baixo
a) (+ 2,5) (- 3/5)

b) 3/8 : 5/4

c) (- 7/9) (+ 2/7) (-1/6)

trinta e cinco pts me ajuda ae :(

Answer 1

Frações:

A)

$\displaystyle \sf \left(\:+2,\:5\right)\:\left(-\:\frac{3}{5}\right)\\\\\\\sf =-2.5\cdot \frac{3}{5}\\\\\\\sf =-\frac{3\cdot \:2.5}{5}\\\\\\\sf =-\frac{7.5}{5}\\\\\\\boxed{\sf -1.5}$

B)

$\sf \displaystyle \sf \frac{3}{8}\:\div \frac{5}{4}$

Multiplicamos as duas frações:

$\sf \displaystyle \sf \frac{3}{8}\times \frac{4}{5} \to \frac{3}{2}\times \frac{1}{5}\to \frac{3\times \:1}{2\times \:5}\to \frac{3}{2\times \:5}\boxed{\sf \frac{3}{10}}$

C)

$\sf \displaystyle \sf \left(-\frac{7}{9}\right)\left(+\frac{2}{7}\right)\left(-\frac{1}{6}\right)\to \frac{7}{9}\cdot \frac{2}{7}\cdot \frac{1}{6}\to \frac{7\cdot \:2\cdot \:1}{9\cdot \:7\cdot \:6}\to \frac{2}{54}\to \boxed{\sf \frac{1}{27} }$