Solve for x
x = \frac{7}{2} = 3\frac{1}{2} = 3.5
x=0
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2x^{2}-7x=0
Subtract 7x from both sides.
x\left(2x-7\right)=0
Factor out x.
x=0 x=\frac{7}{2}
To find equation solutions, solve x=0 and 2x-7=0.
2x^{2}-7x=0
Subtract 7x from both sides.
x=\frac{-\left(-7\right)±\sqrt{\left(-7\right)^{2}}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, -7 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-7\right)±7}{2\times 2}
Take the square root of \left(-7\right)^{2}.
x=\frac{7±7}{2\times 2}
The opposite of -7 is 7.
x=\frac{7±7}{4}
Multiply 2 times 2.
x=\frac{14}{4}
Now solve the equation x=\frac{7±7}{4} when ± is plus. Add 7 to 7.
x=\frac{7}{2}
Reduce the fraction \frac{14}{4} to lowest terms by extracting and canceling out 2.
x=\frac{0}{4}
Now solve the equation x=\frac{7±7}{4} when ± is minus. Subtract 7 from 7.
x=0
Divide 0 by 4.
x=\frac{7}{2} x=0
The equation is now solved.
2x^{2}-7x=0
Subtract 7x from both sides.
\frac{2x^{2}-7x}{2}=\frac{0}{2}
Divide both sides by 2.
x^{2}-\frac{7}{2}x=\frac{0}{2}
Dividing by 2 undoes the multiplication by 2.
x^{2}-\frac{7}{2}x=0
Divide 0 by 2.
x^{2}-\frac{7}{2}x+\left(-\frac{7}{4}\right)^{2}=\left(-\frac{7}{4}\right)^{2}
Divide -\frac{7}{2}, the coefficient of the x term, by 2 to get -\frac{7}{4}. Then add the square of -\frac{7}{4} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-\frac{7}{2}x+\frac{49}{16}=\frac{49}{16}
Square -\frac{7}{4} by squaring both the numerator and the denominator of the fraction.
\left(x-\frac{7}{4}\right)^{2}=\frac{49}{16}
Factor x^{2}-\frac{7}{2}x+\frac{49}{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{7}{4}\right)^{2}}=\sqrt{\frac{49}{16}}
Take the square root of both sides of the equation.
x-\frac{7}{4}=\frac{7}{4} x-\frac{7}{4}=-\frac{7}{4}
Simplify.
x=\frac{7}{2} x=0
Add \frac{7}{4} to both sides of the equation.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
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Matrix
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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}