find a value for k that will make 4x^2 + 6.4x + k a perfect square. again this stuff is kicking my behind
(2x + 1.6)^2 = 4x^2 + 6.4x + 1.6^2,
so if you make k = 1.6^2 = 2.56, you have a perfect square
so if you make k = 1.6^2 = 2.56, you have a perfect square