Answer:
5.9 × 10⁻¹⁶
Explanation:
To solve this, you need to convert one of the two numbers to the same power of ten as the other. We can do that by multiplying the first number by 10:
6.7 × 10⁻¹⁶ - 8.2 × 10⁻¹⁷
= 67× 10⁻¹⁷ - 8.2 × 10⁻¹⁷
= (67 - 8.2) × 10⁻¹⁷
= 58.8 × 10⁻¹⁷
= 5.9 × 10⁻¹⁶
Note that we're rounding to the nearest tenth, as the original numbers given were as well.