Solving or factors the given polynomial.

I have a polynomial and would like to solve it for "r". We can also do factorization if possible but important thing is to find the values of r. We will get possibly three solutions from this polynomial. Following is the equation which we want to solve.

r^3-3r^2(1-h)+3r(1-h)^2+3h(1-h)-1+(wh^3)/Mk

Find all the value of r.

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$$(a-b)^3=a^3-3a^2b+3ab^2-b^3$$
for all $a,b \in \mathbb{R}$.