Cho mik hỏi 2 câu này nx 8x³-12x²+6x-1=0 vs 3x³-6x²+9x=0
1 câu trả lời
8x3−12x2+6x−1=0
⇒(2x−1)3=0
⇒2x−1=0
⇒x=12
3x3−6x2+9x=0
⇒3x(x2−2x+3)=0
⇒3x[(x−1)2+2]=0
Do (x−1)2+2>0 ∀x
⇒3x=0
⇒x=0
8x3−12x2+6x−1=0
⇒(2x−1)3=0
⇒2x−1=0
⇒x=12
3x3−6x2+9x=0
⇒3x(x2−2x+3)=0
⇒3x[(x−1)2+2]=0
Do (x−1)2+2>0 ∀x
⇒3x=0
⇒x=0