What is the difference between the area of a circle with radius 8 units and the sum of the areas of a rectangle with length 10 units and width 5 units, and a parallelogram with base 12 units and height 6 units? Give the answer in square units.
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What is the equation of a circle with a center at (3, -4) and a radius of 5?
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Math Question: "Find the extrema of the function f(x) = 2x^3 - 5x^2 + 4x - 1 on the interval [-2, 3]."