Answer:
-6.62 × 10^(-8)
Explanation:
To simplify the expression (2.8 × 10^−9) − (6.9 × 10^−8), we need to perform the subtraction and then express the result in scientific notation.
(2.8 × 10^−9) − (6.9 × 10^−8) = 2.8 × 10^(-9) - 6.9 × 10^(-8)
To subtract the numbers, we need to ensure that they have the same exponent (power of 10). To do this, we can rewrite 2.8 × 10^(-9) as 0.28 × 10^(-8):
(2.8 × 10^−9) − (6.9 × 10^−8) = 0.28 × 10^(-8) - 6.9 × 10^(-8)
Now, we can subtract the numbers:
0.28 × 10^(-8) - 6.9 × 10^(-8) = (0.28 - 6.9) × 10^(-8) = -6.62 × 10^(-8)
The result is -6.62 × 10^(-8) in scientific notation.