Câu hỏi của Nguyen Chi

Question

A= ( x+2)(x2-2x+4) - (x3-2)

B= (x+2)(x-2)(x2+2x+4)(x2+2x+4)(x2- 2x+4)

C= (x2+3x+1)2+(3x-1)2-2(x2+3x+1)(3x-1)

D= (3x3+3x+1)(3x2-3x+1)-(3x3+1)2

E= (2x2+2x+1)(2x2-2x+1)-(2x2+1)2

Giúp em với ạ.

Dũng Nguyễn · Accepted Answer

$A=\left(x+2\right)\left(x^2-2x+4\right)-\left(x^3-2\right)$

$\Rightarrow A=\left(x^3+8\right)-\left(x^3-2\right)$

$\Rightarrow A=x^3+8-x^3+2$

$\Rightarrow A=\left(x^3-x^3\right)+\left(8+2\right)$

$\Rightarrow A=10$Câu trả lời: $A=\left(x+2\right)\left(x^2-2x+4\right)-\left(x^3-2\right)$

$\Rightarrow A=\left(x^3+8\right)-\left(x^3-2\right)$

$\Rightarrow A=x^3+8-x^3+2$

$\Rightarrow A=\left(x^3-x^3\right)+\left(8+2\right)$

$\Rightarrow A=10$

DƯƠNG PHAN KHÁNH DƯƠNG · Answer

$A=\left(x+2\right)\left(x^2-2x+4\right)-\left(x^3-2\right)$

$=x^3+8-x^3+2$

$=10$

$B=\left(x+2\right)\left(x-2\right)\left(x^2+2x+4\right)\left(x^2-2x+4\right)$

$=\left(x+2\right)\left(x^2-2x+4\right)\left(x-2\right)\left(x^2+2x+4\right)$

$=\left(x^3+8\right)\left(x^3-8\right)$

$=x^6-64$

$C=\left(x^2+3x+1\right)^2+\left(3x-1\right)^2-2\left(x^2+3x+1\right)\left(3x-1\right)$

$=\left(x^2+3x+1\right)^2-2\left(x^2+3x+1\right)\left(3x-1\right)+\left(3x-1\right)^2$

$=\left(x^2+3x+1-3x+1\right)^2$

$=\left(x^2+2\right)^2$

$D=\left(3x^3+3x+1\right)\left(3x^3-3x+1\right)-\left(3x^3+1\right)^2$

$=\left(3x^3+1+3x\right)\left(3x^3+1-3x\right)-\left(3x^3+1\right)^2$

$=\left(3x^3+1\right)^2-9x^2-\left(3x^3+1\right)^2$

$=-9x^2$

$E=\left(2x^2+2x+1\right)\left(2x^2-2x+1\right)-\left(2x^2+1\right)^2$

$=\left(2x^2+1+2x\right)\left(2x^2+1-2x\right)-\left(2x^2+1\right)^2$

$=\left(2x^2+1\right)^2-4x^2-\left(2x^2+1\right)^2$

$=-4x^2$Câu trả lời: $A=\left(x+2\right)\left(x^2-2x+4\right)-\left(x^3-2\right)$