Edugoog
Here, the roots of $x^2 + (k -2)x + 2k + 1 = 0$ being equal, Δ = 0..`. $(k - 2)^2 - 4(2k + 1) = 0$.`. $k^2 - 4k + k - 8k - 4 = 0$.`. $k^2 - 12k = 0$.`. $k(k - 12) = 0$.`. $k = 0$ or $k = 12.$