There is no algorithm to solve this exercise, you only can see that your expression resembles a polynomial, since it is the sum of the powers of a certain quantity (namely x-3), with some coefficient. So, a polynomial described by words would be "pick a constant, add a certain quantity multiplied by some coefficient, then add the square of that quantity multiplied by some coefficient, and so on". And it is exactly what's happening here: you have 11, then you have the first power of x-3 multiplied by 0.5, then you have the second power of x-3 multiplied by -5, and finally you have the fifth power of x-3 multiplied by 2.
So, you have a function f which plays the role of the polynomial:
f(x)=2x^5-5x^2+0.5x+11,
and you're evaluating it at g(x)=x-3 (what I called the "quantity" above).
So, the result is the combination f(g(x))
