Recognize as sum of cubes: Recognize the expression as a sum of two cubes. The given expression is 64+125a3. We can rewrite 64 as (4)3 and 125a3 as (5a)3. This allows us to express the given sum as a sum of cubes: (4)3+(5a)3.
Apply sum of cubes formula: Apply the sum of cubes formula.The sum of cubes formula is a3+b3=(a+b)(a2−ab+b2). We will apply this formula to our expression where a=4 and b=5a.
Substitute values: Substitute the values into the sum of cubes formula.Using the values a=4 and b=5a, we get the factorization (4+5a)((4)2−(4)(5a)+(5a)2).
Simplify factors: Simplify the factors.Now we simplify each factor:First factor: (4+5a) remains the same.Second factor: (4)2−(4)(5a)+(5a)2 simplifies to 16−20a+25a2.
Write final factorization: Write the final factorization.The complete factorization of the expression is (4+5a)(16−20a+25a2).