`a)3x^2-11x+7=0`
`<=>3(x^2-11/3x+7/3)=0`
`<=>x^2-2x. 11/6+121/36-37/36=0`
`<=>(x-11/6)^2=37/36`
`<=>|x-11/6|=\sqrt{37}/6`
`<=>x=[11+-\sqrt{37}]/6`
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`b)5x^2-10x-3=0`
`<=>5(x^2-2x-3/5)=0`
`<=>x^2-2x+1-8/5=0`
`<=>(x-1)^2=8/5`
`<=>|x-1|=[2\sqrt{10}]/5`
`<=>x=[5+-2\sqrt{10}]/5`
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`c)4x^2-12x-5=0`
`<=>4(x^2-3x-5/4)=0`
`<=>x^2-2x. 3/2+9/4-7/2=0`
`<=>(x-3/2)^2=7/2`
`<=>|x-3/2|=\sqrt{14}/2`
`<=>x=[3+-\sqrt{14}]/2`
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`d)5x^2-15x-10=0`
`<=>5(x^2-3x-2)=0`
`<=>x^2-2x. 3/2+9/4-17/4=0`
`<=>(x-3/2)^2=17/4`
`<=>|x-3/2|=\sqrt{17}/2`
`<=>x=[3+-s\qrt{17}]/2`
