Question 154902
(7/8)((10/14)b-48)

= (7/8)(10/14)b - (7/8)(48)

Cancel the 7 with 14 to get:
= (1/8)(10/2)b - (7/8)(48)

Reduce the 10/2 

= (1/8)*5b - (7/8)48

Cancel the 8 with the 48

= (1/8)5b - 7*6

= (5/8)b - 42

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Cheers,
Stan H.