Answer:
(4x + 7) or
(16x^2 - 28x + 49)
Step-by-step explanation:
This is the sum of cubes. If you have choices you really should list them because often the way we write answers is not in agreement with what you are given.
Step One
Factor 64x^3 and 343 into prime factors.
64x^3: 4*4*4*x * x *x
343: 7 * 7 * 7
Step Two
Factor using the sum of cubes.
(4x + 7)([4x]^2 - 7*4x + 7^2)
(4x + 7)(16x^2 - 28x + 49)
