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a fost răspuns

Determinați x €R,știind ca (2x-3)la a doua=3

Răspuns :

Abc112
[tex] {(2x - 3)}^{2} = 3[/tex]

[tex]4 {x}^{2} - 12x + 9 = 3[/tex]

[tex]4 {x}^{2} - 12x + 9 - 3 = 0[/tex]

[tex]4 {x}^{2} - 12x + 6 = 0 \: | \div 2[/tex]

[tex]2 {x}^{2} - 6x + 3 = 0[/tex]

[tex]a = 2[/tex]

[tex]b = - 6[/tex]

[tex]c = 3[/tex]

[tex]\Delta = {b}^{2} - 4ac[/tex]

[tex]\Delta = {( - 6)}^{2} - 4 \times 2 \times 3[/tex]

[tex]\Delta = 36 - 24[/tex]

[tex]\Delta = 12[/tex]

[tex]x_{1,2}=\frac{-b\pm\sqrt{ \Delta}}{2a}[/tex]

[tex]x_{1,2}=\frac{-( - 6)\pm\sqrt{ 12}}{2 \times 2}[/tex]

[tex]x_{1,2}=\frac{6\pm2\sqrt{ 3}}{4}[/tex]

[tex]x_{1}=\frac{6 + 2\sqrt{ 3}}{4}[/tex]

[tex]x_{1}=\frac{2(3+ \sqrt{ 3})}{4}[/tex]

[tex]x_{1}=\frac{3 + \sqrt{ 3}}{2}[/tex]

[tex]x_{2}=\frac{6 - 2\sqrt{ 3}}{4}[/tex]

[tex]x_{2}=\frac{2(3 - \sqrt{ 3})}{4}[/tex]

[tex]x_{2}=\frac{(3 - \sqrt{ 3})}{2}[/tex]