Write an equation for a function that has the graph with the shape of y=x^2, but upside-down and shifted left 5 units

Since we want the function upside-down, the factor muptiplying x^2 mest be -1. To get the function shifted 5 units on left, we must add a term -2*5x = -10x and subtract a constant term 5^2:
y = -x^2 - 10x - 25