a) 3x^2 -2x=0
b) 3x -5x +2=0
c) 2x^2 -3x -2=0
d) 6x^2 -5x +1=0
e) 6x^2 -25x -25=0
g) x^2 -4x +2=0
h) x^2 -2căn3 +2=0
i) x^2 -2x-1=0
k) x^2 -x -2 + căn2=0
l) 4x^2(1+ căn3)x + căn3=0
m) 4x^2 -6x – căn2=0
a) 3x^2 -2x=0
b) 3x -5x +2=0
c) 2x^2 -3x -2=0
d) 6x^2 -5x +1=0
e) 6x^2 -25x -25=0
g) x^2 -4x +2=0
h) x^2 -2căn3 +2=0
i) x^2 -2x-1=0
k) x^2 -x -2 + căn2=0
l) 4x^2(1+ căn3)x + căn3=0
m) 4x^2 -6x – căn2=0
.
a) `3x^2-2x=0`
`<=>x(3x-2)=0`
`<=>` \(\left[ \begin{array}{l}x=0\\3x-2=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=2\\x=\dfrac{2}{3}\end{array} \right.\)
Vậy `S={2;2/3}`
b) `3x^2-5x+2=0`
Có: `a+b+c=0 =>` \(\left[ \begin{array}{l}x=1\\x=\dfrac{2}{3}\end{array} \right.\)
Vậy `S={1;2/3}`
c) `2x^2-3x-2=0`
`<=> (2x^2-4x) + (x-2)=0`
`<=> 2x(x-2)+(x-2)=0`
`<=>(x-2)(2x+1)=0`
`<=>` \(\left[ \begin{array}{l}x=2\\x=\dfrac{-1}{2}\end{array} \right.\)
Vậy `S={2;-1/2}`
d) `6x^2-5x+1=0`
`<=> 6x^2-2x-3x+1=0`
`<=> 2x(3x-1)-(3x-1)=0`
`<=> (3x-1)(2x-1)=0`
`<=>` \(\left[ \begin{array}{l}x=\dfrac{1}{3}\\x=\dfrac{1}{2}\end{array} \right.\)
Vậy `S={1/3 ;1/2}`