Answer:
a=16
Step-by-step explanation:
The distributive property states that
[tex]a(b+c)=ab+ac[/tex]
Therefore using the distributive property
[tex](y - 4x)(y ^ 2 + 4y + 16)[/tex]
=[tex]y(y ^ 2 + 4y + 16) - 4x(y ^ 2 + 4y + 16)[/tex]
Expanding the brackets
[tex]y ^ 3 + 4y^2 + 16y - 4xy ^ 2 - 16xy - 64x[/tex].....(i)
Comparing with the form
[tex]y ^ 3 + 4y ^ 2 + ay - 4x y ^ 2 - axy - 64x[/tex]-----(ii)
The coefficient of y in (i) is 16 which corresponds to a and the likewise the coefficient of xy
Therefore, a=16