To solve this equation, we first need to simplify the expression inside the parentheses:

(-55:5+9) = (-11 + 9) = -2

Now, we can substitute this back into the original equation:

200 (-2 24 + a)

Next, we need to solve the expression inside the parentheses:

-2 * 24 = -48

Now, we substitute this back into the equation:

200 * (-48 + a)

Now, we can simplify further:

-48 + a = -48 + a

So the final expression is:

200 * (-48 + a) = -9600 + 200a

Therefore, the simplified expression is -9600 + 200a.