If the highest common factor (H.C.F.) of the polynomials 4x^2 - 8x and 2x^2 - 6x is k, what is the value of k?

Answer: A. 2x
The H.C.F. of the two polynomials can be found by factoring them: 4x(x - 2) and 2x(x - 3). The common factor is 2x.