Solve for x (complex solution)
x=\frac{-21\sqrt{3}i-21}{2}\approx -10.5-18.186533479i
x=21
x=\frac{-21+21\sqrt{3}i}{2}\approx -10.5+18.186533479i
Solve for x
x=21
Graph
Share
Copied to clipboard
x^{3}=3\times 7\times 441
Cancel out 4\times 22 in both numerator and denominator.
x^{3}=21\times 441
Multiply 3 and 7 to get 21.
x^{3}=9261
Multiply 21 and 441 to get 9261.
x^{3}-9261=0
Subtract 9261 from both sides.
±9261,±3087,±1323,±1029,±441,±343,±189,±147,±63,±49,±27,±21,±9,±7,±3,±1
By Rational Root Theorem, all rational roots of a polynomial are in the form \frac{p}{q}, where p divides the constant term -9261 and q divides the leading coefficient 1. List all candidates \frac{p}{q}.
x=21
Find one such root by trying out all the integer values, starting from the smallest by absolute value. If no integer roots are found, try out fractions.
x^{2}+21x+441=0
By Factor theorem, x-k is a factor of the polynomial for each root k. Divide x^{3}-9261 by x-21 to get x^{2}+21x+441. Solve the equation where the result equals to 0.
x=\frac{-21±\sqrt{21^{2}-4\times 1\times 441}}{2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, 21 for b, and 441 for c in the quadratic formula.
x=\frac{-21±\sqrt{-1323}}{2}
Do the calculations.
x=\frac{-21i\sqrt{3}-21}{2} x=\frac{-21+21i\sqrt{3}}{2}
Solve the equation x^{2}+21x+441=0 when ± is plus and when ± is minus.
x=21 x=\frac{-21i\sqrt{3}-21}{2} x=\frac{-21+21i\sqrt{3}}{2}
List all found solutions.
x^{3}=3\times 7\times 441
Cancel out 4\times 22 in both numerator and denominator.
x^{3}=21\times 441
Multiply 3 and 7 to get 21.
x^{3}=9261
Multiply 21 and 441 to get 9261.
x^{3}-9261=0
Subtract 9261 from both sides.
±9261,±3087,±1323,±1029,±441,±343,±189,±147,±63,±49,±27,±21,±9,±7,±3,±1
By Rational Root Theorem, all rational roots of a polynomial are in the form \frac{p}{q}, where p divides the constant term -9261 and q divides the leading coefficient 1. List all candidates \frac{p}{q}.
x=21
Find one such root by trying out all the integer values, starting from the smallest by absolute value. If no integer roots are found, try out fractions.
x^{2}+21x+441=0
By Factor theorem, x-k is a factor of the polynomial for each root k. Divide x^{3}-9261 by x-21 to get x^{2}+21x+441. Solve the equation where the result equals to 0.
x=\frac{-21±\sqrt{21^{2}-4\times 1\times 441}}{2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, 21 for b, and 441 for c in the quadratic formula.
x=\frac{-21±\sqrt{-1323}}{2}
Do the calculations.
x\in \emptyset
Since the square root of a negative number is not defined in the real field, there are no solutions.
x=21
List all found solutions.
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}