To evaluate the expression (7.1x10^5) - (4.3x10^2), we need to perform the subtraction.
First, let's calculate the subtraction of the coefficients: 7.1 - 4.3 = 2.8.
Next, we need to subtract the exponents of 10^5 and 10^2. Since the subtraction is done between the exponents, we subtract the smaller exponent from the larger exponent: 5 - 2 = 3.
Now we have our result as 2.8x10^3.
In scientific notation, the coefficient is written as a number between 1 and 10, followed by the multiplication symbol "x" and 10 raised to the power of the exponent. Therefore, the expression (7.1x10^5) - (4.3x10^2) is evaluated to 2.8x10^3 in scientific notation.