Guys can you please factor this out for me

21a+8xy^3 −24y^2−7axy

(7 a - 8y^2) x (3-y)

Step-by-step explanation:

21a+8xy^3 −24y^2−7axy

factor out 3 from the expression

3( 7 a - 8 y^2) + 8y^3 - 7 a y

3(7 a - 8 y^2) - y x (-8y^2 + 7 a)

Factor out 7 a - 8y^2 from the expression

(7 a - 8y^2) x (3-y)

= (7 a - 8y^2) x (3-y)

12

step-by-step explanation:

a triangle's   full angle is 180 degrees so 180 - 156 = 24. 24/2=12