`(-18)[36 -: {7-(-2)}] -: (-4){19-(-3)xx(-5)}` = ?

Options

A. `-4.5`
B. 4.5
C. 2.5
D. `-2.5`

Answer

To solve the expression \((-18)[36 -: \{7-(-2)\}] -: (-4)\{19-(-3) \times (-5)\}\), we will break it down step by step.

### Step 1: Simplify the inner expressions
First, we simplify the expressions inside the brackets and curly braces.

1. **Curly braces**:
\[ 7 - (-2) = 7 + 2 = 9 \]
So, we can replace \(\{7 - (-2)\}\) with \(9\).

2. **Second curly braces**:
\[ 19 - (-3) \times (-5) = 19 - (3 \times 5) = 19 - 15 = 4 \]
So, we can replace \(\{19 - (-3) \times (-5)\}\) with \(4\).

Now, the expression looks like this:
\[ (-18)[36 -: 9] -: (-4)[4] \]

### Step 2: Simplify the divisions
Next, we simplify the divisions in the expression.

1. **First division**:
\[ 36 -: 9 = \frac{36}{9} = 4 \]
So, we can replace \([36 -: 9]\) with \(4\).

Now, the expression becomes:
\[ (-18)[4] -: (-4)[4] \]

### Step 3: Multiplication
Now we perform the multiplication:
1. **First multiplication**:
\[ -18 \times 4 = -72 \]

2. **Second multiplication**:
\[ -4 \times 4 = -16 \]

So, the expression now looks like:
\[ -72 -: -16 \]

### Step 4: Final division
Now we perform the final division:
\[ -72 -: -16 = \frac{-72}{-16} = \frac{72}{16} = 4.5 \]

### Final Answer:
The final answer is:
\[ \boxed{4.5} \]