Question

determine as diferenças, me ajudem pfv​

Answer 1

Olá!

Primeiro é necessário calcular o mínimo múltiplo comum em cada caso.

a)

$\dfrac{1}{3} -\dfrac{1}{5} ~~~~~~~~~~~~mmc(3,5)~~~\begin{array}{r|l}3,5&3\\1,5&5\\1,1&~~~~~~3*5=15\end{array}$        →  mmc(3, 5) = 15

$\dfrac{1}{3} -\dfrac{1}{5}~~=~~\dfrac{5-3}{15}~~=~~\dfrac{2}{15}$

b)

$\dfrac{5}{4} -\dfrac{4}{5} ~~~~~~~~~~~~mmc(4,5)~~~\begin{array}{r|l}4,5&4\\1,5&5\\1,1&~~~~~~4*5=20\end{array}$        →  mmc(4, 5) = 20

$\dfrac{5}{4} -\dfrac{4}{5}~~=~~\dfrac{25-16}{20}~~=~~\dfrac{9}{20}$

c)

$\dfrac{3}{1} -\dfrac{2}{5} ~~~~~~~~~~~~mmc(1,5)~~~\begin{array}{r|l}1,5&1\\1,5&5\\1,1&~~~~~~1*5=5\end{array}$             →  mmc(1, 5) = 5

$\dfrac{3}{1} -\dfrac{2}{5}~~=~~\dfrac{15-2}{5}~~=~~\dfrac{13}{5}$

d)

Primeiro vamos resolver as multiplicações.

$3\dfrac{1}{2}-2\dfrac{3}{4} ~=~\dfrac{3}{2} -\dfrac{6}{4} ~=$     Podemos simplificar 6/4 por 2 vamos encontrar 3/2

Portanto:

$3\dfrac{1}{2}-2\dfrac{3}{4} ~=~\dfrac{3}{2} -\dfrac{6}{4} ~=~\dfrac{3}{2} -\dfrac{3}{2}=0$

:)