Identify the values of a, b, and c that would be used in the quadratic formula to solve the equation −x^2 + 5x = 7. a. a = −1, b = 5, c = 0 b. a = 1, b = 5, c = 7 c. a = −1, b = 5, c = −7 d. a = 1, b = −5, c = 0