Math question: "Factorize the expression 4x^2 - 9y^2 using the difference of squares formula."
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What is the speed of a car traveling a distance of 150 km in 2.5 hours?
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Find the value of 'b' if the foci of an ellipse are located at (-3,0) and (3,0), the major axis has a length of 10, and the minor axis has a length of 8.