г) 2c-1 + c+3 = c+3; 9 4 6

г) $$ \frac{2c - 1}{9} + \frac{c + 3}{4} = \frac{c + 3}{6} $$

Приведем дроби к общему знаменателю 36:

$$ \frac{4(2c - 1) + 9(c + 3)}{36} = \frac{6(c + 3)}{36} $$

$$ 8c - 4 + 9c + 27 = 6c + 18 $$

$$ 17c + 23 = 6c + 18 $$

$$ 11c = -5 $$

$$ c = -\frac{5}{11} $$

Ответ: $$\frac{-5}{11}$$