Tentukan batas nilai k agar memiliki penyelesaian y = 4x^2 + (5k-2)x + 15 y = 3x^2 + 4x -1

4x² + (5k-2)x + 15 = 3x² + 4x - 1
4x² - 3x² + (5k-2)x - 4x + 15 + 1 = 0
x² + (5k-6)x + 16 = 0
D ≥ 0
(5k - 6)² - 4(1)(16) ≥ 0
25k² - 60k + 36 - 64 ≥ 0
25k² - 60k - 28 ≥ 0
(5k - 14)(5k + 2) ≥ 0
-2/5 ≤ k ≤ 14/5