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4(5x+1)(5x-1) = 0
1. Take out the GCF (in this case, 4)
4(25x^2-1) = 0
2. This can be further factored. Factor the values within the parenthesis
4(5x + 1)(5x -1) = 0
Answer: 75.4
Steps:
Circumference = 2πr
π = pi
r = radius
2π(12) = 75.39822