Solve for x
x=4
x=\frac{1}{4}=0.25
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x=\frac{4}{9}x^{2}-\frac{8}{9}x+\frac{4}{9}
Use the distributive property to multiply \frac{4}{9} by x^{2}-2x+1.
x-\frac{4}{9}x^{2}=-\frac{8}{9}x+\frac{4}{9}
Subtract \frac{4}{9}x^{2} from both sides.
x-\frac{4}{9}x^{2}+\frac{8}{9}x=\frac{4}{9}
Add \frac{8}{9}x to both sides.
\frac{17}{9}x-\frac{4}{9}x^{2}=\frac{4}{9}
Combine x and \frac{8}{9}x to get \frac{17}{9}x.
\frac{17}{9}x-\frac{4}{9}x^{2}-\frac{4}{9}=0
Subtract \frac{4}{9} from both sides.
-\frac{4}{9}x^{2}+\frac{17}{9}x-\frac{4}{9}=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{-\frac{17}{9}±\sqrt{\left(\frac{17}{9}\right)^{2}-4\left(-\frac{4}{9}\right)\left(-\frac{4}{9}\right)}}{2\left(-\frac{4}{9}\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -\frac{4}{9} for a, \frac{17}{9} for b, and -\frac{4}{9} for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\frac{17}{9}±\sqrt{\frac{289}{81}-4\left(-\frac{4}{9}\right)\left(-\frac{4}{9}\right)}}{2\left(-\frac{4}{9}\right)}
Square \frac{17}{9} by squaring both the numerator and the denominator of the fraction.
x=\frac{-\frac{17}{9}±\sqrt{\frac{289}{81}+\frac{16}{9}\left(-\frac{4}{9}\right)}}{2\left(-\frac{4}{9}\right)}
Multiply -4 times -\frac{4}{9}.
x=\frac{-\frac{17}{9}±\sqrt{\frac{289-64}{81}}}{2\left(-\frac{4}{9}\right)}
Multiply \frac{16}{9} times -\frac{4}{9} by multiplying numerator times numerator and denominator times denominator. Then reduce the fraction to lowest terms if possible.
x=\frac{-\frac{17}{9}±\sqrt{\frac{25}{9}}}{2\left(-\frac{4}{9}\right)}
Add \frac{289}{81} to -\frac{64}{81} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
x=\frac{-\frac{17}{9}±\frac{5}{3}}{2\left(-\frac{4}{9}\right)}
Take the square root of \frac{25}{9}.
x=\frac{-\frac{17}{9}±\frac{5}{3}}{-\frac{8}{9}}
Multiply 2 times -\frac{4}{9}.
x=-\frac{\frac{2}{9}}{-\frac{8}{9}}
Now solve the equation x=\frac{-\frac{17}{9}±\frac{5}{3}}{-\frac{8}{9}} when ± is plus. Add -\frac{17}{9} to \frac{5}{3} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
x=\frac{1}{4}
Divide -\frac{2}{9} by -\frac{8}{9} by multiplying -\frac{2}{9} by the reciprocal of -\frac{8}{9}.
x=-\frac{\frac{32}{9}}{-\frac{8}{9}}
Now solve the equation x=\frac{-\frac{17}{9}±\frac{5}{3}}{-\frac{8}{9}} when ± is minus. Subtract \frac{5}{3} from -\frac{17}{9} by finding a common denominator and subtracting the numerators. Then reduce the fraction to lowest terms if possible.
x=4
Divide -\frac{32}{9} by -\frac{8}{9} by multiplying -\frac{32}{9} by the reciprocal of -\frac{8}{9}.
x=\frac{1}{4} x=4
The equation is now solved.
x=\frac{4}{9}x^{2}-\frac{8}{9}x+\frac{4}{9}
Use the distributive property to multiply \frac{4}{9} by x^{2}-2x+1.
x-\frac{4}{9}x^{2}=-\frac{8}{9}x+\frac{4}{9}
Subtract \frac{4}{9}x^{2} from both sides.
x-\frac{4}{9}x^{2}+\frac{8}{9}x=\frac{4}{9}
Add \frac{8}{9}x to both sides.
\frac{17}{9}x-\frac{4}{9}x^{2}=\frac{4}{9}
Combine x and \frac{8}{9}x to get \frac{17}{9}x.
-\frac{4}{9}x^{2}+\frac{17}{9}x=\frac{4}{9}
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{-\frac{4}{9}x^{2}+\frac{17}{9}x}{-\frac{4}{9}}=\frac{\frac{4}{9}}{-\frac{4}{9}}
Divide both sides of the equation by -\frac{4}{9}, which is the same as multiplying both sides by the reciprocal of the fraction.
x^{2}+\frac{\frac{17}{9}}{-\frac{4}{9}}x=\frac{\frac{4}{9}}{-\frac{4}{9}}
Dividing by -\frac{4}{9} undoes the multiplication by -\frac{4}{9}.
x^{2}-\frac{17}{4}x=\frac{\frac{4}{9}}{-\frac{4}{9}}
Divide \frac{17}{9} by -\frac{4}{9} by multiplying \frac{17}{9} by the reciprocal of -\frac{4}{9}.
x^{2}-\frac{17}{4}x=-1
Divide \frac{4}{9} by -\frac{4}{9} by multiplying \frac{4}{9} by the reciprocal of -\frac{4}{9}.
x^{2}-\frac{17}{4}x+\left(-\frac{17}{8}\right)^{2}=-1+\left(-\frac{17}{8}\right)^{2}
Divide -\frac{17}{4}, the coefficient of the x term, by 2 to get -\frac{17}{8}. Then add the square of -\frac{17}{8} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-\frac{17}{4}x+\frac{289}{64}=-1+\frac{289}{64}
Square -\frac{17}{8} by squaring both the numerator and the denominator of the fraction.
x^{2}-\frac{17}{4}x+\frac{289}{64}=\frac{225}{64}
Add -1 to \frac{289}{64}.
\left(x-\frac{17}{8}\right)^{2}=\frac{225}{64}
Factor x^{2}-\frac{17}{4}x+\frac{289}{64}. 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{17}{8}\right)^{2}}=\sqrt{\frac{225}{64}}
Take the square root of both sides of the equation.
x-\frac{17}{8}=\frac{15}{8} x-\frac{17}{8}=-\frac{15}{8}
Simplify.
x=4 x=\frac{1}{4}
Add \frac{17}{8} 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}