3x2+ 2x- 1= 0
<=> 3x2+ 3x- x- 1= 0
<=> (3x2+ 3x)- (x+ 1)= 0
<=> 3x(x+ 1)- (x+ 1)= 0
<=> (x+1)(3x-1)= 0
<=>\(\orbr{\begin{cases}x+1=0\\3x-1=0\end{cases}}\)
<=> \(\orbr{\begin{cases}x=-1\\3x=1\end{cases}}\)<=> \(\orbr{\begin{cases}x=-1\\x=\frac{1}{3}\end{cases}}\)
Vậy pt có 2 nghiệm S={ -1; 1/3}
\(3x^2+2x-1=0\)
\(\Rightarrow3x^2+3x-x-1=0\)
\(\Rightarrow3x\left(x+1\right)-\left(x+1\right)=0\)
\(\Rightarrow\left(3x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\hept{\begin{cases}3x-1=0\\x+1=0\end{cases}\hept{\begin{cases}3x=1\Rightarrow x=\frac{1}{3}\\x=1\end{cases}}}\)
Vậy x=1/3, x=1
3x^2+2x-1=3x^2+3x-x-1=3x(x+1)-(x+1)=(x+1)(3x-1)
bai nay max easy
X2+2X+1+2X2-2=0
<X+1>2+2<X2-1>=0
<X+1>2+2<X-1><X+1>=0
<X+1><X+1+2X-2>=0
<X+1><3X-1>=0
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