Solve for x (complex solution)
x=\frac{-\sqrt{23}i-1}{4}\approx -0.25-1.198957881i
x=\frac{-1+\sqrt{23}i}{4}\approx -0.25+1.198957881i
Graph
Share
Copied to clipboard
-x^{2}\times 2=x+3
Variable x cannot be equal to any of the values -3,0 since division by zero is not defined. Multiply both sides of the equation by \left(x+3\right)x^{2}, the least common multiple of x+3,x^{2}.
-x^{2}\times 2-x=3
Subtract x from both sides.
-x^{2}\times 2-x-3=0
Subtract 3 from both sides.
-2x^{2}-x-3=0
Multiply -1 and 2 to get -2.
x=\frac{-\left(-1\right)±\sqrt{1-4\left(-2\right)\left(-3\right)}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, -1 for b, and -3 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-1\right)±\sqrt{1+8\left(-3\right)}}{2\left(-2\right)}
Multiply -4 times -2.
x=\frac{-\left(-1\right)±\sqrt{1-24}}{2\left(-2\right)}
Multiply 8 times -3.
x=\frac{-\left(-1\right)±\sqrt{-23}}{2\left(-2\right)}
Add 1 to -24.
x=\frac{-\left(-1\right)±\sqrt{23}i}{2\left(-2\right)}
Take the square root of -23.
x=\frac{1±\sqrt{23}i}{2\left(-2\right)}
The opposite of -1 is 1.
x=\frac{1±\sqrt{23}i}{-4}
Multiply 2 times -2.
x=\frac{1+\sqrt{23}i}{-4}
Now solve the equation x=\frac{1±\sqrt{23}i}{-4} when ± is plus. Add 1 to i\sqrt{23}.
x=\frac{-\sqrt{23}i-1}{4}
Divide 1+i\sqrt{23} by -4.
x=\frac{-\sqrt{23}i+1}{-4}
Now solve the equation x=\frac{1±\sqrt{23}i}{-4} when ± is minus. Subtract i\sqrt{23} from 1.
x=\frac{-1+\sqrt{23}i}{4}
Divide 1-i\sqrt{23} by -4.
x=\frac{-\sqrt{23}i-1}{4} x=\frac{-1+\sqrt{23}i}{4}
The equation is now solved.
-x^{2}\times 2=x+3
Variable x cannot be equal to any of the values -3,0 since division by zero is not defined. Multiply both sides of the equation by \left(x+3\right)x^{2}, the least common multiple of x+3,x^{2}.
-x^{2}\times 2-x=3
Subtract x from both sides.
-2x^{2}-x=3
Multiply -1 and 2 to get -2.
\frac{-2x^{2}-x}{-2}=\frac{3}{-2}
Divide both sides by -2.
x^{2}+\left(-\frac{1}{-2}\right)x=\frac{3}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}+\frac{1}{2}x=\frac{3}{-2}
Divide -1 by -2.
x^{2}+\frac{1}{2}x=-\frac{3}{2}
Divide 3 by -2.
x^{2}+\frac{1}{2}x+\left(\frac{1}{4}\right)^{2}=-\frac{3}{2}+\left(\frac{1}{4}\right)^{2}
Divide \frac{1}{2}, the coefficient of the x term, by 2 to get \frac{1}{4}. Then add the square of \frac{1}{4} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+\frac{1}{2}x+\frac{1}{16}=-\frac{3}{2}+\frac{1}{16}
Square \frac{1}{4} by squaring both the numerator and the denominator of the fraction.
x^{2}+\frac{1}{2}x+\frac{1}{16}=-\frac{23}{16}
Add -\frac{3}{2} to \frac{1}{16} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
\left(x+\frac{1}{4}\right)^{2}=-\frac{23}{16}
Factor x^{2}+\frac{1}{2}x+\frac{1}{16}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x+\frac{1}{4}\right)^{2}}=\sqrt{-\frac{23}{16}}
Take the square root of both sides of the equation.
x+\frac{1}{4}=\frac{\sqrt{23}i}{4} x+\frac{1}{4}=-\frac{\sqrt{23}i}{4}
Simplify.
x=\frac{-1+\sqrt{23}i}{4} x=\frac{-\sqrt{23}i-1}{4}
Subtract \frac{1}{4} from both sides of the equation.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
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}