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Viết biểu thức $\Large (x-3y)(x^2+3xy+9y^2)$ dưới dạng hiệu hai lập

4.7/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Lời giải chi tiết

Câu hỏi:

Viết biểu thức $\Large (x-3y)(x^2+3xy+9y^2)$ dưới dạng hiệu hai lập phương:

A. $\Large x^3+(3y)^3$
B. $\Large x^3+(9y)^3$
C. $\Large x^3-(3y)^3$
D. $\Large x^3-(9y)^3$

Đáp án án đúng là: C

Lời giải chi tiết:

$\Large x^3-(3y)^3= (x-3y)(x^2+x.3y+(3y)^2)=(x-3y)(x^2+3xy+9y^2)$

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