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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: phân tích đa thức thành nhân tử: 1) x mũ 7 + x mũ 2 + 1 2) x mũ 7 + x mũ 5 + 1 3) x mũ 5 + x mũ 4 + 1 4) x mũ 5 + x + 1 5) x mũ 8

Tháng Sáu 29, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: phân tích đa thức thành nhân tử:
1) x mũ 7 + x mũ 2 + 1
2) x mũ 7 + x mũ 5 + 1
3) x mũ 5 + x mũ 4 + 1
4) x mũ 5 + x + 1
5) x mũ 8 + x mũ 7 + 1
6) x mũ 6 – x mũ 4 – 1
7) x mũ 5 + x – 1
8) x mũ 10 + x mũ 5 + 1

Comments ( 1 )

  1. dananhthumai
    dananhthumai
    29 Tháng Sáu, 2022 at 7:34 chiều
    Reply
    ~ gửi bạn ~
    1) x^7 + x^2 + 1
    = x^7 + x^6 – x^6 + x^5 – x^5 + x^4 – x^4 +x^3 – x^3 +2x^2 – x^2 +x – x +1
    =(x^7 + x^6 + x^5) – (x^6 +x^5 +x^4) + (x^4 + x^3 +x^2) – (x^3 +x^2 + x) + (x^2 + x +1)
    =x^5(x^2 + x + 1) – x^4(x^2 + x + 1) +x^2(x^2 + x + 1) – x(x^2 + x + 1) + (x^2 + x + 1)
    =(x^2 + x + 1)(x^5 – x^4 +x^2 -x +1)
    ————————————————
    2) x^7 + x^5 + 1
    = (x^7−x)+(x^5−x^2)+(x^2+x+1)
    = x(x^6−1)+x^2(x^3−1)+(x^2+x+1)
    = x[(x^3)^2−1]+x^2(x−1)(x^2+x+1)+(x^2+x+1)
    = x(x^3−1)(x^3+1)+x^2(x−1)(x^2+x+1)+(x^2+x+1)
    = x(x−1)(x^2+x+1)(x^3+1)+x^2(x−1)(x^2+x+1)+(x^2+x+1)
    =(x^2+x+1)[x(x−1)(x^3+1)+x^2(x−1)+1]
    = ( x^2 + x + 1 ) ( x^ 5 − x ^4 + x ^3 − x + 1 )
    ————————————————
    3) x^5 + x^4 + 1
    =(x^5+x^4+x^3)−(x^3−1)
    = x^3(x^2+x+1)−(x−1)(x^2+x+1)
    =(x^2+x+1)(x^3−x+1)
    ————————————————
    4) x^5 + x + 1
    = x^5+x^4+x^3-x^4-x^3-x^2+x^2+x+1
    =x^3.(x^2+x+1)-x^2.(x^2+x+1)+(x^2+x+1)
    =(x^2+x+1)(x^3 – x^2 + 1)
    ————————————————
    5) x^8 + x^7 + 1
    = x^8+x^7+x^6+x^5+x^4+x^3+x^2+x-x^6-x^5-x^4-x^3-x^2-x+1
    = x^6(x^2+x+1)+x^3(x^2+x+1)+(x^2+x+1)-x^4(x^2+x+1)-x(x^2+x+1)
    = (x^2+x+1)(x^6+x^3+1-x^4-x)
    ————————————————
    6) x^6 – x^4 – 1
    (mik ko biết làm)
    ————————————————
    7) x^5 + x – 1
    =(x^5+x^2)−(x^2−x+1)
    = x^2(x^3+1)−(x^2−x+1)
    = x^2(x+1)(x^2−x+1)−(x^2−x+1)
    = (x^2−x+1)(x^3+x^2−1)
    ————————————————
    8) x^10 + x^5 + 1
    =x^10-x+x^5-x^2+x^2+x+1
    =x.(x^9-1)+x2.(x^3-1)+(x^2+x+1)
    =x.(x^3-1)(x^3+1)+x^2(x^3-1)+(x^2-x+1)
    =x.(x-1)(x^2+x+1)(x^3+1)+x^2(x-1)(x^2+x+1)+(x^2+x+1)
    =(x^2+x+1)[x.(x-1)(x^3+1)+x^2(x-1)+1]
    =(x^2+x+1)(x^5+x^2-x^4-x+x^3-x^2+1)
    =(x^2+x+1)(x^5-x^4+x^3-x+1)

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222-9+11+12:2*14+14 = ? ( )

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