Hi there!
For this, we are given a set of equations which is then equal to f(x), a function based off an input x. This means that we can correspond x to the input and f(x), or what the functions are equal to, to the output.
This means we can essentially just try inputs into the equations, and see if the output matches:
x * 5 - 11:
2 * 5 - 11 = 10 - 11 = -1, not the output, thus this isn't the equation.
x^3 + 3:
2 ^ 3 + 3 = 8 + 3 = 11
3 ^ 3 + 3 = 27 + 3 = 30
4 ^ 3 + 3 = 64 + 3 = 67
5 ^ 3 + 3 = 125 + 3 = 128
As we can see, all of these inputs and outputs match, this means that this equation is the correct one. Therefore, your answer is the second choice, x^3 + 3.
Hope this helps!
