Câu hỏi của Nguyễn Linh Chi

Question

bài 1: rút gọn biểu thức1. x(x-1)(x+1) - (x+1)(x2-x+1)2. (2a2+2a+1) ( 2a2-2a+1) - (2a2+1)23. (a2+b2+c2)2 - (a2-b2-c2)24. (a+b+c+d) (a+b+c+d)5. (a-5)2 (a2+10a+25)6. (3x$^3$+3x+1) (3x$^3$-3x+1) - (3...

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$

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