Find the value of s which makes the following equation true
`s-5-{5-4+(7xx6-12-:3)}=-40`

Options

A. `-12`
B. `-4`
C. `4`
D. `12`

Answer

To solve the equation \( s - 5 - \{ 5 - 4 + (7 \times 6 - 12 \div 3) \} = -40 \), we will follow these steps:

### Step 1: Simplify the expression inside the curly brackets
Start with the expression \( 7 \times 6 - 12 \div 3 \).

1. Calculate \( 7 \times 6 \):
\[ 7 \times 6 = 42 \]

2. Calculate \( 12 \div 3 \):
\[ 12 \div 3 = 4 \]

3. Now substitute these values back into the expression:
\[ 42 - 4 = 38 \]

### Step 2: Substitute the simplified value back into the equation
Now substitute \( 38 \) back into the equation:
\[ s - 5 - \{ 5 - 4 + 38 \} = -40 \]

### Step 3: Simplify the expression inside the curly brackets
Now simplify \( 5 - 4 + 38 \):
\[ 5 - 4 = 1 \]
\[ 1 + 38 = 39 \]

### Step 4: Substitute this value back into the equation
Now substitute \( 39 \) back into the equation:
\[ s - 5 - 39 = -40 \]

### Step 5: Combine like terms
Combine \( -5 \) and \( -39 \):
\[ s - 44 = -40 \]

### Step 6: Solve for \( s \)
Add \( 44 \) to both sides of the equation:
\[ s = -40 + 44 \]
\[ s = 4 \]

### Final Answer
The value of \( s \) that makes the equation true is:
\[ \boxed{4} \]