Question

Which expression is equal to 5.1×10−3?(1 point)
Responses

2.9×10−3+1.2×10−3
2.9 times 10 negative cubed plus 1.2 times 10 negative cubed

2.2×10−1+2.9×10−2
2.2 times 10 superscript negative 1 baseline plus 2.9 times 10 negative squared

3.9×10−3+1.2×10−3
3.9 times 10 negative cubed plus 1.2 times 10 negative cubed

3.5×103+1.6×10^−6

Answer 1

To determine which expression is equal to \( 5.1 \times 10^{-3} \), we need to simplify each response:

1. \( 2.9 \times 10^{-3} + 1.2 \times 10^{-3} \):
\[
(2.9 + 1.2) \times 10^{-3} = 4.1 \times 10^{-3}
\]

2. \( 2.2 \times 10^{-1} + 2.9 \times 10^{-2} \):
Convert \( 2.2 \times 10^{-1} \) to the same exponent as \( 2.9 \times 10^{-2} \):
\[
2.2 \times 10^{-1} = 22 \times 10^{-2}
\]
Then:
\[
22 \times 10^{-2} + 2.9 \times 10^{-2} = (22 + 2.9) \times 10^{-2} = 24.9 \times 10^{-2} = 2.49 \times 10^{-1}
\]

3. \( 3.9 \times 10^{-3} + 1.2 \times 10^{-3} \):
\[
(3.9 + 1.2) \times 10^{-3} = 5.1 \times 10^{-3}
\]

4. \( 3.5 \times 10^{3} + 1.6 \times 10^{-6} \):
This expression doesn't combine with \( 10^{-3} \) and is not equal to \( 5.1 \times 10^{-3} \).

Thus, the correct expression that equals \( 5.1 \times 10^{-3} \) is:

**3.9 × 10^−3 + 1.2 × 10^−3**