Could anyone explain this question in detail?

h and k are simply variables that stand in for the x and y of a point. Math books could have easily have used x1, x2 y1 to, but h and k is the convention.

anyway, this is a guess n check question. Substitute the x value of the point for h, and y value for k, and whichever one gives you a true equation is the right one.

your answer would be 10x - 1