3:(6/7-3/4)

To solve the expression 3:(6/7-3/4), we need to simplify it step by step:

1. First, calculate the values within the parentheses: 6/7 = 0.857 (rounded to three decimal places) 3/4 = 0.75

2. Subtract the two values: 0.857 - 0.75 = 0.107

3. Now, divide 3 by the result obtained in step 2: 3 / 0.107 ≈ 28.037 (rounded to three decimal places)

Therefore, the answer to the expression 3:(6/7-3/4) is approximately 28.037.