If x is a real number, what is the maximum possible value of the expression -x^2 + 8t -4?
-x^2 + 8t -4?
-x^2 + 8x - 4
-x^2 +8x-4 is a dome shaped parabola the max will occur (at the vertex) at the value of x = - b/2a where b = 8 a = -1
use this value of 'x' in the equation to calculate the maximum value of the equation