Evaluate:
`(75-68)-[23-(51-45)]`

Answer

To evaluate the expression `(75 - 68) - [23 - (51 - 45)]`, we will follow these steps:

### Step 1: Solve the innermost bracket
First, we will solve the expression inside the innermost brackets, which is `51 - 45`.

**Calculation:**
\[ 51 - 45 = 6 \]

### Step 2: Substitute back into the expression
Now we substitute this result back into the expression. The expression now looks like this:
\[ (75 - 68) - [23 - 6] \]

### Step 3: Solve the next bracket
Next, we solve the expression inside the square brackets, which is `23 - 6`.

**Calculation:**
\[ 23 - 6 = 17 \]

### Step 4: Substitute back into the expression
Now we substitute this result back into the expression. The expression now looks like this:
\[ (75 - 68) - 17 \]

### Step 5: Solve the first part of the expression
Now we will solve the first part of the expression, which is `75 - 68`.

**Calculation:**
\[ 75 - 68 = 7 \]

### Step 6: Substitute back into the expression
Now we substitute this result back into the expression. The expression now looks like this:
\[ 7 - 17 \]

### Step 7: Final calculation
Finally, we will subtract `17` from `7`.

**Calculation:**
\[ 7 - 17 = -10 \]

### Final Answer
The final answer is:
\[ -10 \]

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