Solve for x
x=\sqrt{5}\approx 2.236067977
x=-\sqrt{5}\approx -2.236067977
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6\times 3-\left(3x^{2}-3\right)=1+x^{2}
Variable x cannot be equal to any of the values -1,1 since division by zero is not defined. Multiply both sides of the equation by 6\left(x-1\right)\left(x+1\right)\left(x^{2}+1\right), the least common multiple of x^{4}-1,2x^{2}+2,6-6x^{2}.
18-\left(3x^{2}-3\right)=1+x^{2}
Multiply 6 and 3 to get 18.
18-3x^{2}+3=1+x^{2}
To find the opposite of 3x^{2}-3, find the opposite of each term.
21-3x^{2}=1+x^{2}
Add 18 and 3 to get 21.
21-3x^{2}-x^{2}=1
Subtract x^{2} from both sides.
21-4x^{2}=1
Combine -3x^{2} and -x^{2} to get -4x^{2}.
-4x^{2}=1-21
Subtract 21 from both sides.
-4x^{2}=-20
Subtract 21 from 1 to get -20.
x^{2}=\frac{-20}{-4}
Divide both sides by -4.
x^{2}=5
Divide -20 by -4 to get 5.
x=\sqrt{5} x=-\sqrt{5}
Take the square root of both sides of the equation.
6\times 3-\left(3x^{2}-3\right)=1+x^{2}
Variable x cannot be equal to any of the values -1,1 since division by zero is not defined. Multiply both sides of the equation by 6\left(x-1\right)\left(x+1\right)\left(x^{2}+1\right), the least common multiple of x^{4}-1,2x^{2}+2,6-6x^{2}.
18-\left(3x^{2}-3\right)=1+x^{2}
Multiply 6 and 3 to get 18.
18-3x^{2}+3=1+x^{2}
To find the opposite of 3x^{2}-3, find the opposite of each term.
21-3x^{2}=1+x^{2}
Add 18 and 3 to get 21.
21-3x^{2}-1=x^{2}
Subtract 1 from both sides.
20-3x^{2}=x^{2}
Subtract 1 from 21 to get 20.
20-3x^{2}-x^{2}=0
Subtract x^{2} from both sides.
20-4x^{2}=0
Combine -3x^{2} and -x^{2} to get -4x^{2}.
-4x^{2}+20=0
Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.
x=\frac{0±\sqrt{0^{2}-4\left(-4\right)\times 20}}{2\left(-4\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -4 for a, 0 for b, and 20 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-4\right)\times 20}}{2\left(-4\right)}
Square 0.
x=\frac{0±\sqrt{16\times 20}}{2\left(-4\right)}
Multiply -4 times -4.
x=\frac{0±\sqrt{320}}{2\left(-4\right)}
Multiply 16 times 20.
x=\frac{0±8\sqrt{5}}{2\left(-4\right)}
Take the square root of 320.
x=\frac{0±8\sqrt{5}}{-8}
Multiply 2 times -4.
x=-\sqrt{5}
Now solve the equation x=\frac{0±8\sqrt{5}}{-8} when ± is plus.
x=\sqrt{5}
Now solve the equation x=\frac{0±8\sqrt{5}}{-8} when ± is minus.
x=-\sqrt{5} x=\sqrt{5}
The equation is now solved.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
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Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}