Answer:
20x³ -45x
Explanation:
The least common multiple of two expressions is the product of their unique factors.
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4x³ -9x = x(4x² -9) = x(2x -3)(2x +3) . . . . factors of 1st expression
10x² -15x = 5x(2x -3) . . . . . . . . . . . . . . . . factors of 2nd expression
The unique factors are 5, x, (2x -3), and (2x +3). Their product is ...
5(4x³ -9x) = 20x³ -45x . . . . least common multiple