8/23/2014
If
f(x) = 3x2
+
4x + 5, what must the value of k
be
so that the graph of f(x – k)
is symmetric about the y-axis?
a) -4 b) -4/3 c) -2/3
d) 2/3 e) 4/3
Scroll down for the solution.
8/23/2014 Solution. D. Upon completing the square, f(x) = 3(x + 2/3)2 + 11/3, with the Axis of Symmetry being x = -2/3 so that f(x – 2/3) would shift it 2/3 units to the right and make it symmetric about the y-axis, so k = -2/3.