Solve {l}{A=2a^{4}-a^{3}-8a^2+5a+11}{B=-5a^4-7a^3-42a^2}{c=-9a+5}

$$\left. \begin{array} { l } { A = 2 a ^ { 4 } - a ^ { 3 } - 8 a ^ { 2 } + 5 a + 11 } \\ { B = - 5 a ^ { 4 } - 7 a ^ { 3 } - 42 a ^ { 2 } } \\ { c = - 9 a + 5 } \end{array} \right.$$

Solve for A, a, B, c (complex solution)

$$A=2a^{4}-a^{3}-8a^{2}+5a+11$$

$$a\in \mathrm{C}$$

$$B=-a^{2}\left(5a^{2}+7a+42\right)$$

$$c=5-9a$$

Solve for A, a, B, c

$$A=2a^{4}-a^{3}-8a^{2}+5a+11$$

$$a\in \mathrm{R}$$

$$B=-a^{2}\left(5a^{2}+7a+42\right)$$

$$c=5-9a$$