Toán Lớp 8: Giải phương trình: x^5 = x^4 + x^3 + x^2 + x + 2
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Toán Lớp 8: Giải phương trình: x^5 = x^4 + x^3 + x^2 + x + 2
Comments ( 2 )
=> x^5 – x^4 – x^3 – x^2 – x – 2 =0
=> x^4.(x-2) + x^3.(x-2) + x^2.(x-2) + x.(x-2) + (x-2) = 0
=> (x-2).(x^4+x^3+ x^2 + x + 1) =0
=>x-2=0
Nên cuối cùng x =2
<=> x^5 – x^4 – x^3 – x^2 – x – 2 =0
<=> x^5 – 2x^4 + x^4 – 2x^3 + x^3 – 2x^2 + x^2 – 2x + x-2 =0
<=> x^4.(x-2) + x^3.(x-2) + x^2.(x-2) + x.(x-2) + (x-2) = 0
<=> (x-2).(x^4+x^3+ x^2 + x + 1) =0
<=>x-2=0