Answer :
Sure, let's solve this multiplication problem step-by-step.
1. Identify the numbers to be multiplied:
[tex]\[
21 \quad \text{and} \quad -7
\][/tex]
2. Perform the multiplication:
[tex]\[
21 \times (-7)
\][/tex]
3. Determine the sign of the result:
- When you multiply a positive number by a negative number, the result is always negative.
4. Calculate the product:
- Multiply the absolute values of the numbers:
[tex]\[
21 \times 7 = 147
\][/tex]
- Add the negative sign to the result:
[tex]\[
-147
\][/tex]
Therefore, [tex]\( 21 \times (-7) = -147 \)[/tex].
From the provided options, the correct answer is:
[tex]\[
\boxed{-147}
\][/tex]
1. Identify the numbers to be multiplied:
[tex]\[
21 \quad \text{and} \quad -7
\][/tex]
2. Perform the multiplication:
[tex]\[
21 \times (-7)
\][/tex]
3. Determine the sign of the result:
- When you multiply a positive number by a negative number, the result is always negative.
4. Calculate the product:
- Multiply the absolute values of the numbers:
[tex]\[
21 \times 7 = 147
\][/tex]
- Add the negative sign to the result:
[tex]\[
-147
\][/tex]
Therefore, [tex]\( 21 \times (-7) = -147 \)[/tex].
From the provided options, the correct answer is:
[tex]\[
\boxed{-147}
\][/tex]
