Respuesta :

 24x^2 - 6xy -63y^2 
Factor out the common factor: 
3 (8x^2 - 2xy - 21y^2 ) 
Factor what remains in parentheses: 
3 (4x - 7y) (2x + 3y)
I think the answers is 3(4x-7y) (2x+3y )