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3x^{2}-5=12
Subtract 10 from 5 to get -5.
3x^{2}=12+5
Add 5 to both sides.
3x^{2}=17
Add 12 and 5 to get 17.
x^{2}=\frac{17}{3}
Divide both sides by 3.
x=\frac{\sqrt{51}}{3} x=-\frac{\sqrt{51}}{3}
Take the square root of both sides of the equation.
3x^{2}-5=12
Subtract 10 from 5 to get -5.
3x^{2}-5-12=0
Subtract 12 from both sides.
3x^{2}-17=0
Subtract 12 from -5 to get -17.
x=\frac{0±\sqrt{0^{2}-4\times 3\left(-17\right)}}{2\times 3}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 3 for a, 0 for b, and -17 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 3\left(-17\right)}}{2\times 3}
Square 0.
x=\frac{0±\sqrt{-12\left(-17\right)}}{2\times 3}
Multiply -4 times 3.
x=\frac{0±\sqrt{204}}{2\times 3}
Multiply -12 times -17.
x=\frac{0±2\sqrt{51}}{2\times 3}
Take the square root of 204.
x=\frac{0±2\sqrt{51}}{6}
Multiply 2 times 3.
x=\frac{\sqrt{51}}{3}
Now solve the equation x=\frac{0±2\sqrt{51}}{6} when ± is plus.
x=-\frac{\sqrt{51}}{3}
Now solve the equation x=\frac{0±2\sqrt{51}}{6} when ± is minus.
x=\frac{\sqrt{51}}{3} x=-\frac{\sqrt{51}}{3}
The equation is now solved.