Final answer:
To subtract rational expressions, find a common denominator and then subtract the numerators. The correct subtraction of the given rational expressions is (-2x + 6)/((x - 1)(x + 3)).
Step-by-step explanation:
To subtract rational expressions, we need a common denominator. In this case, the common denominator is (x - 1)(x + 3). So, we rewrite the expressions as:
1/(x - 1) - 3/(x^2 + 2x - 3) = (1(x + 3) - 3(x - 1))/((x - 1)(x + 3))
Simplifying the numerator, we get (x + 3 - 3x + 3)/((x - 1)(x + 3)) = (-2x + 6)/((x - 1)(x + 3))
Therefore, the correct subtraction of the rational expressions is (-2x + 6)/((x - 1)(x + 3)).