Question

下列計算正確的是

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A．5y²·4yx²＝9x³y³

B．(－2x³yⁿz)(－4xⁿ⁺¹y^n－3)＝8xⁿ⁺⁴y^2n－3

C．(－x^n－2y²)(－xy^m)²＝－xⁿy^2m+2

D．(－7a²b³)(5ab²c)＝－2a²b⁶c

Answer 1

答案：C
解析：

A項5y2·4yx2＝20x2y3；B項(－2x3ynz)(－4xn+1yn－3)＝8xn+4y2n－3z；C項(－xn－2y2)(－xym)2＝(－xn－2y2)·(x2y2m)＝－xny2m+2；D項(－7a2b3)(5ab2c)＝－35a3b5c．