## problem statement

Calculate the volume of the tetrahedron with vertices at points $A_{1}, A_{2}, A_{3}, A_{4}$ and its height dropped from vertex $A_{4}$ to the face $A_{1} A_{2} A_{3}$.

$A_{1}(0 ;-1 ;-1)$

$A_{2}(-2 ; 3 ; 5)$

$A_{3}(1 ;-5 ;-9)$

$A_{4}(-1 ;-6 ; 3)$