Solve for x (complex solution)
x=\frac{3+\sqrt{7}i}{2}\approx 1.5+1.322875656i
x=\frac{-\sqrt{7}i+3}{2}\approx 1.5-1.322875656i
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x^{2}+4=x\times 3
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x^{2}, the least common multiple of x^{2},x.
x^{2}+4-x\times 3=0
Subtract x\times 3 from both sides.
x^{2}+4-3x=0
Multiply -1 and 3 to get -3.
x^{2}-3x+4=0
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
x=\frac{-\left(-3\right)±\sqrt{\left(-3\right)^{2}-4\times 4}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -3 for b, and 4 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-3\right)±\sqrt{9-4\times 4}}{2}
Square -3.
x=\frac{-\left(-3\right)±\sqrt{9-16}}{2}
Multiply -4 times 4.
x=\frac{-\left(-3\right)±\sqrt{-7}}{2}
Add 9 to -16.
x=\frac{-\left(-3\right)±\sqrt{7}i}{2}
Take the square root of -7.
x=\frac{3±\sqrt{7}i}{2}
The opposite of -3 is 3.
x=\frac{3+\sqrt{7}i}{2}
Now solve the equation x=\frac{3±\sqrt{7}i}{2} when ± is plus. Add 3 to i\sqrt{7}.
x=\frac{-\sqrt{7}i+3}{2}
Now solve the equation x=\frac{3±\sqrt{7}i}{2} when ± is minus. Subtract i\sqrt{7} from 3.
x=\frac{3+\sqrt{7}i}{2} x=\frac{-\sqrt{7}i+3}{2}
The equation is now solved.
x^{2}+4=x\times 3
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x^{2}, the least common multiple of x^{2},x.
x^{2}+4-x\times 3=0
Subtract x\times 3 from both sides.
x^{2}+4-3x=0
Multiply -1 and 3 to get -3.
x^{2}-3x=-4
Subtract 4 from both sides. Anything subtracted from zero gives its negation.
x^{2}-3x+\left(-\frac{3}{2}\right)^{2}=-4+\left(-\frac{3}{2}\right)^{2}
Divide -3, the coefficient of the x term, by 2 to get -\frac{3}{2}. Then add the square of -\frac{3}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-3x+\frac{9}{4}=-4+\frac{9}{4}
Square -\frac{3}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}-3x+\frac{9}{4}=-\frac{7}{4}
Add -4 to \frac{9}{4}.
\left(x-\frac{3}{2}\right)^{2}=-\frac{7}{4}
Factor x^{2}-3x+\frac{9}{4}. 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{3}{2}\right)^{2}}=\sqrt{-\frac{7}{4}}
Take the square root of both sides of the equation.
x-\frac{3}{2}=\frac{\sqrt{7}i}{2} x-\frac{3}{2}=-\frac{\sqrt{7}i}{2}
Simplify.
x=\frac{3+\sqrt{7}i}{2} x=\frac{-\sqrt{7}i+3}{2}
Add \frac{3}{2} to 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}