Trang chủ » Hỏi đáp » Môn Toán tìm x a) x^3 – 6x^2 + 9x = 0 b) 5x ( x – 2012 ) – x + 2012 = 0 01/08/2024 tìm x a) x^3 – 6x^2 + 9x = 0 b) 5x ( x – 2012 ) – x + 2012 = 0
a) x^3-6x^2+9x=0 ⇔x(x^2-6x+9)=0 ⇔x(x-3)^2=0 ⇔x=0 hoặc (x-3)^2=0 TH1 : x=0 TH2 : (x-3)^2=0 ⇔x-3=0 ⇔x=3 Vậy xin{0;3} b) 5x(x-2012)-x+2012=0 ⇔5x(x-2012)-(x-2012)=0 ⇔(5x-1)(x-2012)=0 ⇔5x-1=0 hoặc x-2012=0 TH1 : 5x-1=0 ⇔5x=1 ⇔x=1/5 TH2 : x-2012=0 ⇔x=2012 Vậy xin{1/5;2012} Trả lời
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