Question

realizar las sustracciones
-(-7/9)-(9-15)
-(3/16)-(7/20)

Answer 1

- (- 7 / 9) - ( 9 - 15 ) = 7/9 - 9 + 15 = 7/9 + 6 = (7 + 54) / 9 = 61 / 9 

m.c.m. (9, 1 ) = 9

- ( 3 / 16 ) - ( 7 / 20 ) = - 3/16 - 7/20 = (-15 - 28) / 80 = - 43 / 80 

m.c.m (16,20) = 2⁴ . 5 = 80