4.3x10^14 - 7.5x10^14

To subtract these two numbers in scientific notation, we need to ensure that both numbers have the same exponent.

Let's rewrite both numbers with the same exponent:

4.3 × 10^14 - 7.5 × 10^14 = (4.3 - 7.5) × 10^14

Now, subtract the coefficients:

4.3 - 7.5 = -3.2

Therefore, the result is -3.2 × 10^14.