If the roots of the equation lgx = 8-2x x ∈ (k, K + 1), K ∈ Z, then k = () A. 2B. 3C. 4D. 5

Let f (x) = lgx + 2x-8, then the function f (x) increases monotonically at (0, + ∞), and the function is continuous at (0, + ∞) ∵ f (1) = - 6 ＜ 0, f (2) = lg2-4 ＜ 0, f (3) = lg3-2 ＜ 0, f (4) = LG4 ＞ 0  f (3) f (4) ＜ 0, which can be obtained from the zero determination theorem of the function, and the zero interval of the function (3, 4) ∵ k = 3, so select: B

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