Question 7 • Common Core Algebra I B-IC
Write the expression as a sum of cubes: 125x⁹ + 64 = (5x³)³ + 4³. Use the sum-of-cubes rule, a³ + b³ = (a + b)(a² − ab + b²), with a = 5x³ and b = 4. This gives (5x³ + 4)(25x⁶ − 20x³ + 16), which is choice C.
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