No one got the correct answer. The answer is supposed to be 7(2d+3k-dk-1). All the coefficients are divisible by 7, thus only the integers are changed. However, the variables cannot be a factor because they do not have the same variables that all the coefficients must have.
Sounds like you're asked to find

such that

In other words, find

that satisfies

We can factorize this as

In order that

describes a probability distribution, require that

for all

, which means we can ignore the possibility of

.
Let

.


Multiply both sides by

.

We want to find

that removes the quartic and quadratic terms from the equation, i.e.

so the cubic above transforms to

Substitute

and we get

![\implies y=\sqrt[3]{\dfrac{9+\sqrt{93}}{18}}](https://tex.z-dn.net/?f=%5Cimplies%20y%3D%5Csqrt%5B3%5D%7B%5Cdfrac%7B9%2B%5Csqrt%7B93%7D%7D%7B18%7D%7D)
Step-by-step explanation:

The equation is 70 35
----- = ------
100 x
To solve, multiply diagonally
You should get 70x = 3500
Then to get x alone, divide each side by 70
Your answer should be 50