Remember:
The product of the sum of two perfect cubes:
a³ + b³ = (a + b)(a² - ab + b²)
The product of the difference of two perfect cubes:
a³ - b³ = (a - b)(a² + ab + b²)
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Remember to follow PEMDAS.
(5c)(5c) = 25c²
(5c)(-2/3) = -10c/3
(2/3)(5c) = 10c/3
(2/3)(-2/3) = -4/9
25c²- 10c/3 + 10c/3 - 4/9
Combine like terms
25c² (-10c/3 + 10c/3) - 4/9
25c² - 4/9
25c² - 4/9 is your answer
hope this helps
