#### Answer

(a) (30.974 x 4) + (10 x 16) = 283.896 u
(b) (6 x 12) + (1 x 7) + (1 x 14) = 95 u
(c) (1 x 3) + (30.974) + (4 x 16) = 97.974 u

#### Work Step by Step

We find, using the atomic masses on the periodic table:
(a) (30.974 x 4) + (10 x 16) = 283.896 u
(b) (6 x 12) + (1 x 7) + (1 x 14) = 95 u
(c) (1 x 3) + (30.974) + (4 x 16) = 97.974 u