54:(21-15)*8-(62:7)-134-128

To solve the expression \(54:(21-15)*8-(62:7)-134-128\), we will follow the order of operations (parentheses, exponents, multiplication and division (from left to right), addition and subtraction (from left to right)).

1. Start with the parentheses: \[ 21 - 15 = 6 \] So now we have: \[ 54:(6)*8 - (62:7) - 134 - 128 \]

2. Next, handle the divisions:

   • \(54 : 6 = 9\)
   • \(62 : 7 \approx 8.857143\) (exact fraction is \(\frac{62}{7}\))

   Now the expression looks like: \[ 9 * 8 - 8.857143 - 134 - 128 \]

3. Next, calculate the multiplication: \[ 9 * 8 = 72 \]

   So now we have: \[ 72 - 8.857143 - 134 - 128 \]

4. Now perform the subtractions from left to right:

   • First, \(72 - 8.857143 \approx 63.142857\)
   • Next, \(63.142857 - 134 = -70.857143\)
   • Finally, \(-70.857143 - 128 = -198.857143\)

Thus, the final answer is approximately: \[ \boxed{-198.86} \] (rounded to two decimal places).