1)[imath]x^2-14x+13=0[/imath]
[imath]\iff (x^2-x) + (13x-13)=0[/imath]
[imath]\iff x(x-1)+13(x-1)=0[/imath]
[imath]\iff(x-1)(x+13)=0[/imath]
[imath]\iff \left[\begin{matrix} x-1=0\\ x+13=0\end{matrix}\right.[/imath]
[imath]\iff \left[\begin{matrix} x=1\\ x=-13\end{matrix}\right.[/imath]
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2)[imath]4x^2-4x-3=0[/imath]
[imath]\iff (4x^2 + 2x) + (-6x-3)=0[/imath]
[imath]\iff 2x(2x+1) -3(2x+1)=0[/imath]
[imath]\iff ( 2x+1)(2x-3)=0[/imath]
[imath]\iff \left[\begin{matrix} 2x+1=0\\ 2x-3=0\end{matrix}\right.[/imath]
[imath]\iff \left[\begin{matrix} x=\dfrac{-1}{2}\\ x=\dfrac{3}{2}\end{matrix}\right.[/imath]
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3)[imath]4x^2-12x-7=0[/imath]
[imath]\iff(4x^2+2x) + (-14x-7)=0[/imath]
[imath]\iff 2x(2x+1) - 7(2x+1)=0[/imath]
[imath]\iff (2x+1)(2x-7)=0[/imath]
[imath]\iff \left[\begin{matrix} 2x+1=0\\ 2x-7=0\end{matrix}\right.[/imath]
[imath]\iff \left[\begin{matrix} x=\dfrac{1}{2}\\ x=\dfrac{7}{2}\end{matrix}\right.[/imath]
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4.[imath]x^3-6x^2+12x-8=0[/imath]
[imath]\iff x^3 - 3.x^2.2 + 3.x.2^2 - 2^3=0[/imath]
[imath]\iff (x-2)^3=0[/imath]
[imath]\iff x-2=0[/imath]
[imath]\iff x = 2[/imath]
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5.[imath]x^3 = 4x[/imath]
[imath]\iff x^3 - 4x=0[/imath]
[imath]\iff x(x^2-4)=0[/imath]
[imath]\iff x(x-2)(x+2)=0[/imath]
[imath]\iff \left[\begin{matrix} x=0\\ x-2=0 \\ x+2=0\end{matrix}\right.[/imath]
[imath]\iff \left[\begin{matrix} x=0\\ x=2 \\ x=-2\end{matrix}\right.[/imath]
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
