Question

what rational number should be subtracted from 8/9 to get -3/4​

Answer 1

Let, the number be x

Then,

(-4/9) - x = 5/12

⇒ x = - 4/9 - 5/12

= ( - 16 - 15 )/36, since LCM (9, 12) = 36

= ( - 31 )/36

= (-31/36)

Therefore, (-31/36) should be subtracted from (-4/9) to get 5/12.

2)

Let, the other number be y.

Then,

y + (-5/7) = -8/9

⇒ y = - 8/9 - (-5/7)

= -8/9 + 5/7

= ( - 56 + 45 )/63, since LCM (9, 7) = 63

= (- 11)/63

= (-11/63)

Therefore, the other number be (-11/63).