Solve for x
x=-1
x = \frac{3}{2} = 1\frac{1}{2} = 1.5
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7-2x=4x^{2}-4x+1
Add 4 and 3 to get 7.
7-2x-4x^{2}=-4x+1
Subtract 4x^{2} from both sides.
7-2x-4x^{2}+4x=1
Add 4x to both sides.
7+2x-4x^{2}=1
Combine -2x and 4x to get 2x.
7+2x-4x^{2}-1=0
Subtract 1 from both sides.
6+2x-4x^{2}=0
Subtract 1 from 7 to get 6.
3+x-2x^{2}=0
Divide both sides by 2.
-2x^{2}+x+3=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=1 ab=-2\times 3=-6
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as -2x^{2}+ax+bx+3. To find a and b, set up a system to be solved.
-1,6 -2,3
Since ab is negative, a and b have the opposite signs. Since a+b is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product -6.
-1+6=5 -2+3=1
Calculate the sum for each pair.
a=3 b=-2
The solution is the pair that gives sum 1.
\left(-2x^{2}+3x\right)+\left(-2x+3\right)
Rewrite -2x^{2}+x+3 as \left(-2x^{2}+3x\right)+\left(-2x+3\right).
-x\left(2x-3\right)-\left(2x-3\right)
Factor out -x in the first and -1 in the second group.
\left(2x-3\right)\left(-x-1\right)
Factor out common term 2x-3 by using distributive property.
x=\frac{3}{2} x=-1
To find equation solutions, solve 2x-3=0 and -x-1=0.
7-2x=4x^{2}-4x+1
Add 4 and 3 to get 7.
7-2x-4x^{2}=-4x+1
Subtract 4x^{2} from both sides.
7-2x-4x^{2}+4x=1
Add 4x to both sides.
7+2x-4x^{2}=1
Combine -2x and 4x to get 2x.
7+2x-4x^{2}-1=0
Subtract 1 from both sides.
6+2x-4x^{2}=0
Subtract 1 from 7 to get 6.
-4x^{2}+2x+6=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{-2±\sqrt{2^{2}-4\left(-4\right)\times 6}}{2\left(-4\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -4 for a, 2 for b, and 6 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-2±\sqrt{4-4\left(-4\right)\times 6}}{2\left(-4\right)}
Square 2.
x=\frac{-2±\sqrt{4+16\times 6}}{2\left(-4\right)}
Multiply -4 times -4.
x=\frac{-2±\sqrt{4+96}}{2\left(-4\right)}
Multiply 16 times 6.
x=\frac{-2±\sqrt{100}}{2\left(-4\right)}
Add 4 to 96.
x=\frac{-2±10}{2\left(-4\right)}
Take the square root of 100.
x=\frac{-2±10}{-8}
Multiply 2 times -4.
x=\frac{8}{-8}
Now solve the equation x=\frac{-2±10}{-8} when ± is plus. Add -2 to 10.
x=-1
Divide 8 by -8.
x=-\frac{12}{-8}
Now solve the equation x=\frac{-2±10}{-8} when ± is minus. Subtract 10 from -2.
x=\frac{3}{2}
Reduce the fraction \frac{-12}{-8} to lowest terms by extracting and canceling out 4.
x=-1 x=\frac{3}{2}
The equation is now solved.
7-2x=4x^{2}-4x+1
Add 4 and 3 to get 7.
7-2x-4x^{2}=-4x+1
Subtract 4x^{2} from both sides.
7-2x-4x^{2}+4x=1
Add 4x to both sides.
7+2x-4x^{2}=1
Combine -2x and 4x to get 2x.
2x-4x^{2}=1-7
Subtract 7 from both sides.
2x-4x^{2}=-6
Subtract 7 from 1 to get -6.
-4x^{2}+2x=-6
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{-4x^{2}+2x}{-4}=-\frac{6}{-4}
Divide both sides by -4.
x^{2}+\frac{2}{-4}x=-\frac{6}{-4}
Dividing by -4 undoes the multiplication by -4.
x^{2}-\frac{1}{2}x=-\frac{6}{-4}
Reduce the fraction \frac{2}{-4} to lowest terms by extracting and canceling out 2.
x^{2}-\frac{1}{2}x=\frac{3}{2}
Reduce the fraction \frac{-6}{-4} to lowest terms by extracting and canceling out 2.
x^{2}-\frac{1}{2}x+\left(-\frac{1}{4}\right)^{2}=\frac{3}{2}+\left(-\frac{1}{4}\right)^{2}
Divide -\frac{1}{2}, the coefficient of the x term, by 2 to get -\frac{1}{4}. Then add the square of -\frac{1}{4} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-\frac{1}{2}x+\frac{1}{16}=\frac{3}{2}+\frac{1}{16}
Square -\frac{1}{4} by squaring both the numerator and the denominator of the fraction.
x^{2}-\frac{1}{2}x+\frac{1}{16}=\frac{25}{16}
Add \frac{3}{2} to \frac{1}{16} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
\left(x-\frac{1}{4}\right)^{2}=\frac{25}{16}
Factor x^{2}-\frac{1}{2}x+\frac{1}{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{1}{4}\right)^{2}}=\sqrt{\frac{25}{16}}
Take the square root of both sides of the equation.
x-\frac{1}{4}=\frac{5}{4} x-\frac{1}{4}=-\frac{5}{4}
Simplify.
x=\frac{3}{2} x=-1
Add \frac{1}{4} 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}