Express the function f(x) = −x 2 + 8x − 11 in standard form and use it to graph the function.

Answer 1

y= -x^2 +8x -11 = -(x^2 -8x ) -11, complete the square

= -(x^2 -8x + 16) - 11+ 16

=-(x-4)^2 + 5, vertex is (4,5). It's a downward opening parabola with maximum point (4,5)