5x^3 - 12x - x^2 + 9 - 12x^5 - 6x^4 - k = 19 + 8x^3 - 18x - 19x^5 - 2x^2 - 8x^4

k = 7x^5 + 2x^4 - 3x^3 + 6x - 10?

yes