Solve for x
x=1
x=3
Graph
Quiz
Quadratic Equation
5 problems similar to:
\frac { 1 } { 2 } x ^ { 2 } - 2 x + \frac { 3 } { 2 } = 0
Share
Copied to clipboard
\frac{1}{2}x^{2}-2x+\frac{3}{2}=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(-2\right)±\sqrt{\left(-2\right)^{2}-4\times \frac{1}{2}\times \frac{3}{2}}}{2\times \frac{1}{2}}
This equation is in standard form: ax^{2}+bx+c=0. Substitute \frac{1}{2} for a, -2 for b, and \frac{3}{2} for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-2\right)±\sqrt{4-4\times \frac{1}{2}\times \frac{3}{2}}}{2\times \frac{1}{2}}
Square -2.
x=\frac{-\left(-2\right)±\sqrt{4-2\times \frac{3}{2}}}{2\times \frac{1}{2}}
Multiply -4 times \frac{1}{2}.
x=\frac{-\left(-2\right)±\sqrt{4-3}}{2\times \frac{1}{2}}
Multiply -2 times \frac{3}{2}.
x=\frac{-\left(-2\right)±\sqrt{1}}{2\times \frac{1}{2}}
Add 4 to -3.
x=\frac{-\left(-2\right)±1}{2\times \frac{1}{2}}
Take the square root of 1.
x=\frac{2±1}{2\times \frac{1}{2}}
The opposite of -2 is 2.
x=\frac{2±1}{1}
Multiply 2 times \frac{1}{2}.
x=\frac{3}{1}
Now solve the equation x=\frac{2±1}{1} when ± is plus. Add 2 to 1.
x=3
Divide 3 by 1.
x=\frac{1}{1}
Now solve the equation x=\frac{2±1}{1} when ± is minus. Subtract 1 from 2.
x=1
Divide 1 by 1.
x=3 x=1
The equation is now solved.
\frac{1}{2}x^{2}-2x+\frac{3}{2}=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{1}{2}x^{2}-2x+\frac{3}{2}-\frac{3}{2}=-\frac{3}{2}
Subtract \frac{3}{2} from both sides of the equation.
\frac{1}{2}x^{2}-2x=-\frac{3}{2}
Subtracting \frac{3}{2} from itself leaves 0.
\frac{\frac{1}{2}x^{2}-2x}{\frac{1}{2}}=-\frac{\frac{3}{2}}{\frac{1}{2}}
Multiply both sides by 2.
x^{2}+\left(-\frac{2}{\frac{1}{2}}\right)x=-\frac{\frac{3}{2}}{\frac{1}{2}}
Dividing by \frac{1}{2} undoes the multiplication by \frac{1}{2}.
x^{2}-4x=-\frac{\frac{3}{2}}{\frac{1}{2}}
Divide -2 by \frac{1}{2} by multiplying -2 by the reciprocal of \frac{1}{2}.
x^{2}-4x=-3
Divide -\frac{3}{2} by \frac{1}{2} by multiplying -\frac{3}{2} by the reciprocal of \frac{1}{2}.
x^{2}-4x+\left(-2\right)^{2}=-3+\left(-2\right)^{2}
Divide -4, the coefficient of the x term, by 2 to get -2. Then add the square of -2 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-4x+4=-3+4
Square -2.
x^{2}-4x+4=1
Add -3 to 4.
\left(x-2\right)^{2}=1
Factor x^{2}-4x+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-2\right)^{2}}=\sqrt{1}
Take the square root of both sides of the equation.
x-2=1 x-2=-1
Simplify.
x=3 x=1
Add 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}