Math question: Given triangle ABC, angle bisector BD intersects side AC at point D. If angle B is 50 degrees and angle C is 80 degrees, find the measure of angle A. (
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Math question: Find the derivative of f(x) = 3x^2 + 5√x + 8ln(x) - 7e^x.
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What is the maximum value of the function f(x) = x^2 - 4x + 3 in the interval [0, 5]?