3(x^2+10x+5)-5(x-k)=
3x^2+30x+15-5x+5k=
3x^2+25x+15+5k
for this to be divisible by x every term must include x or get eliminated
the problematic terms are 15 and 5k
to eliminate them they must equal 0 when added:
15+5k=0
5k=-15
k=-3
so A) -3 is the solution
A complex fraction means that there must be a fraction in the numerator or denomenator or both
so
some are
Given the additional information you provided, the value of a determines how quickly the quadratic grows. Increasing this causes the function to grow faster.
For future reference, the constants h and k relate to translating the function along the x and y axes respectively
