Solve for x
x=\frac{8}{9}\approx 0.888888889
x=0
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x=9x\left(1-x\right)
Multiply 3 and 3 to get 9.
x=9x-9x^{2}
Use the distributive property to multiply 9x by 1-x.
x-9x=-9x^{2}
Subtract 9x from both sides.
-8x=-9x^{2}
Combine x and -9x to get -8x.
-8x+9x^{2}=0
Add 9x^{2} to both sides.
x\left(-8+9x\right)=0
Factor out x.
x=0 x=\frac{8}{9}
To find equation solutions, solve x=0 and -8+9x=0.
x=9x\left(1-x\right)
Multiply 3 and 3 to get 9.
x=9x-9x^{2}
Use the distributive property to multiply 9x by 1-x.
x-9x=-9x^{2}
Subtract 9x from both sides.
-8x=-9x^{2}
Combine x and -9x to get -8x.
-8x+9x^{2}=0
Add 9x^{2} to both sides.
9x^{2}-8x=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(-8\right)±\sqrt{\left(-8\right)^{2}}}{2\times 9}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 9 for a, -8 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-8\right)±8}{2\times 9}
Take the square root of \left(-8\right)^{2}.
x=\frac{8±8}{2\times 9}
The opposite of -8 is 8.
x=\frac{8±8}{18}
Multiply 2 times 9.
x=\frac{16}{18}
Now solve the equation x=\frac{8±8}{18} when ± is plus. Add 8 to 8.
x=\frac{8}{9}
Reduce the fraction \frac{16}{18} to lowest terms by extracting and canceling out 2.
x=\frac{0}{18}
Now solve the equation x=\frac{8±8}{18} when ± is minus. Subtract 8 from 8.
x=0
Divide 0 by 18.
x=\frac{8}{9} x=0
The equation is now solved.
x=9x\left(1-x\right)
Multiply 3 and 3 to get 9.
x=9x-9x^{2}
Use the distributive property to multiply 9x by 1-x.
x-9x=-9x^{2}
Subtract 9x from both sides.
-8x=-9x^{2}
Combine x and -9x to get -8x.
-8x+9x^{2}=0
Add 9x^{2} to both sides.
9x^{2}-8x=0
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
\frac{9x^{2}-8x}{9}=\frac{0}{9}
Divide both sides by 9.
x^{2}-\frac{8}{9}x=\frac{0}{9}
Dividing by 9 undoes the multiplication by 9.
x^{2}-\frac{8}{9}x=0
Divide 0 by 9.
x^{2}-\frac{8}{9}x+\left(-\frac{4}{9}\right)^{2}=\left(-\frac{4}{9}\right)^{2}
Divide -\frac{8}{9}, the coefficient of the x term, by 2 to get -\frac{4}{9}. Then add the square of -\frac{4}{9} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-\frac{8}{9}x+\frac{16}{81}=\frac{16}{81}
Square -\frac{4}{9} by squaring both the numerator and the denominator of the fraction.
\left(x-\frac{4}{9}\right)^{2}=\frac{16}{81}
Factor x^{2}-\frac{8}{9}x+\frac{16}{81}. 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{4}{9}\right)^{2}}=\sqrt{\frac{16}{81}}
Take the square root of both sides of the equation.
x-\frac{4}{9}=\frac{4}{9} x-\frac{4}{9}=-\frac{4}{9}
Simplify.
x=\frac{8}{9} x=0
Add \frac{4}{9} to both sides of the equation.
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
\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}