Câu hỏi của LỢI

Question

Rút gọn các biểu thưc sau:c.(x -1)3 – (x - 1)(x2 +x+1)d.(x -3)3 – (x - 3)(x2 +3x+9) + 6(x+1)2Mình cần gấp!!!!!

Minh Hiếu · Accepted Answer

c) $\left(x-1\right)^3-\left(x-1\right)\left(x^2+x+1\right)$$=\left(x-1\right)^3-\left(x-1\right)\left(x^2+x.1+1^2\right)$$=\left(x-1\right)^3-\left(x-1\right)^3$$=0$Câu trả lời: c) $\left(x-1\right)^3-\left(x-1\right)\left(x^2+x+1\right)$$=\left(x-1\right)^3-\left(x-1\right)\left(x^2+x.1+1^2\right)$$=\left(x-1\right)^3-\left(x-1\right)^3$$=0$

Minh Hiếu · Answer

d) $\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2$$=\left(x-3\right)^3-\left(x-3\right)\left(x^2+x.3+3^2\right)+6\left(x+1\right)^2$$=\left(x-3\right)^3-\left(x-3\right)^3+6\left(x+1\right)^2$$=0+6\left(x+1\right)^2$$=6\left(x+1\right)^2$Câu trả lời: d) $\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2$$=\left(x-3\right)^3-\left(x-3\right)\left(x^2+x.3+3^2\right)+6\left(x+1\right)^2$$=\left(x-3\right)^3-\left(x-3\right)^3+6\left(x+1\right)^2$$=0+6\left(x+1\right)^2$$=6\left(x+1\right)^2$

hưng phúc · Answer

c. (x - 1)3 - (x - 1)(x2 + x + 1)= (x - 1)3 - (x3 - 1)= x3 - 2x2 + 2x - 1 - x3 + 1= x3 - x3 - 2x2 + 2x - 1 + 1= -2x2 + 2xd. (x - 3)3 - (x - 3)(x2 + 3x + 9) + 6(x + 1)2= x3 - 6x2 + 18x - 27 - (x3 - 27) + 6(x2 + 2x + 1)= x3 - 6x2 + 18x - 27 - x3 + 27 + 6x2 + 12x + 6= x3 - x3 - 6x2 + 6x2 + 18x + 12x - 27 + 27 + 6= 30x + 6Câu trả lời: c. (x - 1)3 - (x - 1)(x2 + x + 1)= (x - 1)3 - (x3 - 1)= x3 - 2x2 + 2x - 1 - x3 + 1= x3 - x3 - 2x2 + 2x - 1 + 1= -2x2 + 2xd. (x - 3)3 - (x - 3)(x2 + 3x + 9) + 6(x + 1)2= x3 - 6x2 + 18x - 27 - (x3 - 27) + 6(x2 + 2x + 1)= x3 - 6x2 + 18x - 27 - x3 + 27 + 6x2 + 12x + 6= x3 - x3 - 6x2 + 6x2 + 18x + 12x - 27 + 27 + 6= 30x + 6

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