Which function in vertex form is equivalent to f(x) = 4 + x2 – 2x? f(x) = (x – 1)2 + 3 f(x) = (x – 1)2 + 5 f(x) = (x + 1)2 + 3 f(x) = (x + 1)2 + 5

To express a function of the form  in vertex form  where (h,k) is the vertex of the parabola, we need to find the vertex first.
To find the vertex we are going to use the vertex formula: , and  will be the function evaluated at .
We can infer from our function that  and . So lets find :




Now that we have , we can evaluate the function at 1 to find :





We have the vertex (1,3) of our parabola, so we can use its vertex form:




We can conclude that the vertex for of our parabola is f(x) = (x + 1)2 + 3.