Question

TÌM X

a) \(3x^2-2x-5=0\)

b)\(x^2-x-6=0\)

c) \(x^2-12x+35=0\)

Answer 1

a, \(3x^2-2x-5=0\)

\(\Rightarrow3x^2+3x-5x-5=0\)

\(\Rightarrow3x\left(x+1\right)-5\left(x+1\right)=0\)

\(\Rightarrow\left(3x-5\right)\left(x+1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}3x-5=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=-1\end{matrix}\right.\)

b, \(x^2-x-6=0\)

\(\Rightarrow x^2+2x-3x-6=0\)

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

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

\(\Rightarrow\left[{}\begin{matrix}x-3=0\\x+2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)

c, \(x^2-12x+35=0\)

tương tự

Answer 2

a: \(\Leftrightarrow3x^2-5x+3x-5=0\)

=>(3x-5)(x+1)=0

=>x=5/3 hoặc x=-1

b: \(\Leftrightarrow\left(x-3\right)\left(x+2\right)=0\)

=>x=3 hoặc x=-2

c: =>(x-7)(x-5)=0

=>x=7 hoặc x=5