Question

(9/4-2/3)*(20/8+9/6)

Answer 1

mmc de 4 e 3 = 12
mmc de 8 e 6 = 24

(27-8/12)*(60+36/24)
19/12*96/24
19/12*4
76/12 (divide tudo por 4 para simplificar) 
 Resposta: 19/3

Answer 2

$( \frac{9}{4} - \frac{2}{3} ) . ( \frac{20}{8} + \frac{9}{6} )= \\ \\ ( \frac{2 \f7 - 8}{12} ) . ( \frac{60 + 36}{24} )= \\ \\ \\ \frac{19}{12} . \frac{96}{24} = \\ \\ \frac{96}{24} : \frac{24}{24} = 4 \\ \\ \frac{19}{12} . 4 = \frac{19}{3}$