Question

efetue estas operações e,quando possível apresente a resposta na forma irredutível
(precisoooo pra amanha)
​

Answer 1

a)

$\begin{array}{rcl}\left(+\dfrac{1}{9}\right)+\left(-\dfrac{2}{9}\right) &=& \dfrac{1}{9}-\dfrac{2}{9} \\ &=& -\dfrac{1}{9}\end{array}$

b)

$\begin{array}{rcl}(-9{,}6)-(-2{,}5) &=& -9{,}6+2{,}5 \\ \\ &=& -7{,}1 \end{array}$

c)

$\begin{array}{rcl}\left(-\dfrac{7}{30}\right)+\left(+\dfrac{4}{30}\right)+\left(-\dfrac{11}{30}\right) &=& -\dfrac{7}{30}+\dfrac{4}{30}-\dfrac{11}{30} \\ \\ &=& \dfrac{-7+4-11}{30} \\ \\ &=& -\dfrac{14}{30} \\ \\ &=& -\dfrac{7}{15} \end{array}$

d)

$\begin{array}{rcl}(-4{,}1)+(-15{,}2) &=& -4{,}1-15{,}2 \\ \\ &=& -19{,}3 \end{array}$

e)

$\begin{array}{rcl}\left(+\dfrac{2}{3}\right)+\left(-\dfrac{1}{8}\right) &=& \dfrac{2}{3}-\dfrac{1}{8} \\ \\ &=& \dfrac{2\cdot 8}{3\cdot 8} -\dfrac{1\cdot 3}{8\cdot 3} \\ \\ &=& \dfrac{16}{24}-\dfrac{3}{24} \\ \\ &=& \dfrac{13}{24}\end{array}$

f)

$\begin{array}{rcl}\left(-\dfrac{1}{5}\right)-\left(+\dfrac{2}{3}\right)+\left(-\dfrac{1}{4}\right) &=& -\dfrac{1}{5}-\dfrac{2}{3}-\dfrac{1}{4}\\ \\ &=&-\dfrac{1\cdot 3\cdot 4}{5\cdot 3\cdot 4}-\dfrac{2\cdot 5\cdot 4}{3\cdot 5\cdot 4}-\dfrac{1\cdot 5\cdot 3}{4\cdot 5\cdot 3} \\ \\ &=& -\dfrac{12}{60}-\dfrac{40}{60}-\dfrac{15}{60}\\ \\ &=& \dfrac{-12-40-15}{60} \\ \\ &=&- \dfrac{67}{60} \end{array}$

Espero ter ajudado :D