Câu hỏi của Nguyễn Linh Chi

Question

bài 1: rút gọn biểu thức

1. x(x-1)(x+1) - (x+1)(x²-x+1)

2. (2a²+2a+1) ( 2a²-2a+1) - (2a²+1)²

3. (a²+b²...

phan thị minh anh · Accepted Answer

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

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

$\left(a^2+b^2+c^2+a^2-b^2-c^2\right)\left(a^2+b^2+c^2-a^2+b^2+c^2\right)=2a^2\left(2b^2+2c^2\right)=4a^2b^2+4a^2c^2$

$\left(a-5\right)^2\left(a+5\right)^2=\left(a^2-25\right)^2$

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

Câu trả lời:

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

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

$\left(a^2+b^2+c^2+a^2-b^2-c^2\right)\left(a^2+b^2+c^2-a^2+b^2+c^2\right)=2a^2\left(2b^2+2c^2\right)=4a^2b^2+4a^2c^2$

$\left(a-5\right)^2\left(a+5\right)^2=\left(a^2-25\right)^2$

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