Question

pls answer for this question ​

Answer 1

$Let \: the \: number \: to \: be \: substracted\: be \: 'x', \\ \\ ∴ (11a + 4b - 12c) - x = (3c- 2b + 5a) \\ \\ ∴ ( - x) = 3c- 2b + 5a - 11a - 4b + 12c \\ \\ ∴( - x) = 3c + 12c - 2b - 4b + 5a - 11a \\ \\ ∴ ( - x)= 15c - 6b - 6a \\ \\ ∴ x = - 15c + 6b + 6a \\ \\ ∴ \green{ \boxed{x = 6a + 6b - 15c}}$