Find the coordinates of the vertex for the parabola -x^2-4+7

Write a recursive sequence that represents the sequence defined by the following explicit formula:

5× 1/2 = ? a) more than 5 because you are multiplying by a whole number b) 5/10 because you multiply the numerator and denominator by 5 c) less than 5 because you are multiplying by a number that is more than 1 d) less than 5 because you are multiplying by a number that is less than 1

Could somebody me with this radical simplification?