Question

a) 3x( x² - 5x + 3 ) + ( x+ 1).(x+2)

b) ( x + 2 )² + ( x -3 )² - ( x- 1). ( x + 1)

Khai triển rõ ràng từng bước; ko tóm tắt hoặc ghi mỗi đáp số

 

Answer 1

\(3x\left(x^2-5x+3\right)+\left(x+1\right)\left(x+2\right)\)

\(=3x^3-15x^2+9x+x^2+2x+x+2\)

\(=3x^3-14x^2+13x+2\)

Answer 2

a/ \(3x\left(x^2-5x+3\right)+\left(x+1\right)\left(x+2\right)\)

\(=3x^3-15x^2+9x+\left(x^2+2x+x+2\right)\)

\(=3x^3-15x^2+9x+x^2+2x+x+2\)

\(=3x^3-14x^2+13x+2\)

b/ \(\left(x+2\right)^2+\left(x-3\right)^2-\left(x-1\right)\left(x+1\right)\)

\(=\left(x^2+4x+4\right)+\left(x^2-6x+9\right)-\left(x^2-1\right)\)

\(=x^2+4x+4+x^2-6x+9-x^2+1\)

\(=x^2-2x+14x\)

Answer 3

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

\(=x^2+4x+4+x^2-6x+9-\left(x^2-1\right)\)

\(=2x^2-2x+13-x^2+1\)

\(=x^2-2x+14\)

Answer 4

a) \(3x\left(x^2-5x+3\right)+\left(x+1\right)\left(x+2\right)\)

\(=3x^3-15x^2+9x+\left(x^2+2x+x+2\right)\)

\(=3x^3-14x^2+12x+2\)

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

\(=\left(x^2+4x+4\right)+\left(x^2-6x+9\right)-\left(x^2+x-x-1\right)\)

\(=x^2+4x+4+x^2-6x+9-x^2+1\)

\(=x^2-2x+14\)

Answer 5

sorry làm sai kết quả :)))) già rồi tính đơn giản cx sai :3 Thực lòng xin lỗi

sửa kết quả cuối 2 câu

a/ \(=3x^3-14x^2+12x+2.\)

b/\(=x^2-2x+14\)

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