7(4+3/4)-(33/4-5)
7(4+3/4)-(9/4-5)
7(16/4+3/4)-(9/4-20/4)
7*(19/4)-(29/4)
133/4 - 29/4
104/4

Итак, 7(4+3/4)-(33/4-5) при с=3/4 равно 26.