Use the [TEX][ /TEX] tags, not the [tex][/MATH ] ones.
Finish and simplify and see what you get.
According to Edward T. Dowling within Schaum's Outline of Theory and problem of Mathematical methods for business and economics:
(3x^3 - 5x^2 y^2 - 2y^3)(7x-4y) = 21x^2 - 12x^y - 35x^3y^2 +20x^2y^3 - 14xy^3 + 8y^4
Can you clarify?
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