​Determine the Angle $\theta$ Through Which the Axes Are Rotated $3 x ^ { 2 } - 9 x y + 11 y ^ { 2 } + ( 3 \sqrt { 10 } - 9 ) x - ( 5 \sqrt { 10 } + 10 ) y = 91$

Multiple Choice

​Determine the angle $\theta$ through which the axes are rotated.Round your answer to two decimal places. $3 x ^ { 2 } - 9 x y + 11 y ^ { 2 } + ( 3 \sqrt { 10 } - 9 ) x - ( 5 \sqrt { 10 } + 10 ) y = 91$ ​​

A) $\theta = 79.87 ^ { \circ }$
B) $\theta = 78.87 ^ { \circ }$
C) $\theta = 80.87 ^ { \circ }$
D) $\theta = 77.87 ^ { \circ }$
E) $\theta = 81.87 ^ { \circ }$