Try C, i am not completely sure but i tried
(f+g-k)(x) means to add the equations f(x) and g(x) then subtract k(x)
2x^2 + 3x + 4x - 9 = 2x^2 +7x -9
2x^2 + 7x - 9 - x^2 -7x = x^2 -9
The answer is : x^2 - 9
Use the equation (x2-x1)/(y2-y1)
Substitute the value of x and y
Switch y and x to find the inverse:
x = 3y - 8
Now just solve for y
y = x/3 + 8/3
