Algebra: A Combined Approach (4th Edition)

$\dfrac{5}{6}x^{4}-7x^{3}-19$
$\dfrac{2}{3}x^{4}+12x^{3}+\dfrac{1}{6}x^{4}-19x^{3}-19$ Simplify by combining like terms: $\Big(\dfrac{2}{3}+\dfrac{1}{6}\Big)x^{4}+(12-19)x^{3}-19=...$ $...=\Big(\dfrac{12+3}{18}\Big)x^{4}-7x^{3}-19=\dfrac{15}{18}x^{4}-7x^{3}-19=...$ $...=\dfrac{5}{6}x^{4}-7x^{3}-19$