Question

tìm x biết

x^2-6x+9=(2x+1)^2

Answer 1

\(x^2-6x+9=\left(2x+1\right)^2\)

\(\Rightarrow\left(x-3\right)^2=\left(2x+1\right)^2\)

\(\Rightarrow\left(x-3\right)^2-\left(2x+1\right)^2=0\)

\(\Rightarrow\left(x-3-2x-1\right)\left(x-3+2x+1\right)=0\)

\(\Rightarrow-\left(x+4\right)\left(3x-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+4=0\\3x-2=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-4\\x=\frac{2}{3}\end{cases}}\)

Answer 2

x^2-6x+9=(2x+1)^2

<=>x²-6x+9=4x²+4x+1

<=>3x²+10x-8=0

<=>3x²-2x+12x-8=0

<=>x(3x-2)+4(3x-2)=0

<=>(x+4)(3x-2)=0

<=>x=-4 hoặc x=2/3

Answer 3

x²-6x+9=(2x+1)²

\(\Rightarrow\)(x-3)²=(2x+1)²

\(\Rightarrow\)(x-3-2x-1)(x-3+2x+1)=0

\(\Rightarrow\)-(x+4)(3x-2)=0

\(\Rightarrow\)\(\orbr{\begin{cases}x+4=0\\3x-2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-4\\x=\frac{2}{3}\end{cases}}}\)