Question

si A es los 2/3 de 9/7 y B es los 5/4 de los 2/3
hallar A - B

Answer 1

A = (2/3)(9/7) = [(2x9)/(3x7)] = (2x3)/(7) = 6/7

B = (5/4)(2/3) = [(5x2)/(4x3)] = (5)/(2x3) = 5/6

A = 6/7;  B = 5/6

A - B = 6/7 - 5/6 = [(6x6) - (5x7)]/42 = (36 - 35)/42 = 1/42

A - B = 1/42

Answer 2

si A es los 2/3 "de" 9/7 la palabra "de" traduciendo al lenguaje matemático es multiplicación.
sabiendo esto planteamos.
A =(2/3)(9/7) =18/21 simplificando
A = 6/7
B = (5/4)(2/3) = 10/12 simplificando
B = 5/6
hallamos:
A - B
A-B = 6/7 - 5/6
A-B (36 - 35)/42
A-B = 1/42 :)