Solve for x
x = -\frac{3}{2} = -1\frac{1}{2} = -1.5
x=2
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3\left(x+2\right)=x\left(x+1\right)\times 2
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 3x, the least common multiple of x,3.
3x+6=x\left(x+1\right)\times 2
Use the distributive property to multiply 3 by x+2.
3x+6=\left(x^{2}+x\right)\times 2
Use the distributive property to multiply x by x+1.
3x+6=2x^{2}+2x
Use the distributive property to multiply x^{2}+x by 2.
3x+6-2x^{2}=2x
Subtract 2x^{2} from both sides.
3x+6-2x^{2}-2x=0
Subtract 2x from both sides.
x+6-2x^{2}=0
Combine 3x and -2x to get x.
-2x^{2}+x+6=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 6=-12
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as -2x^{2}+ax+bx+6. To find a and b, set up a system to be solved.
-1,12 -2,6 -3,4
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 -12.
-1+12=11 -2+6=4 -3+4=1
Calculate the sum for each pair.
a=4 b=-3
The solution is the pair that gives sum 1.
\left(-2x^{2}+4x\right)+\left(-3x+6\right)
Rewrite -2x^{2}+x+6 as \left(-2x^{2}+4x\right)+\left(-3x+6\right).
2x\left(-x+2\right)+3\left(-x+2\right)
Factor out 2x in the first and 3 in the second group.
\left(-x+2\right)\left(2x+3\right)
Factor out common term -x+2 by using distributive property.
x=2 x=-\frac{3}{2}
To find equation solutions, solve -x+2=0 and 2x+3=0.
3\left(x+2\right)=x\left(x+1\right)\times 2
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 3x, the least common multiple of x,3.
3x+6=x\left(x+1\right)\times 2
Use the distributive property to multiply 3 by x+2.
3x+6=\left(x^{2}+x\right)\times 2
Use the distributive property to multiply x by x+1.
3x+6=2x^{2}+2x
Use the distributive property to multiply x^{2}+x by 2.
3x+6-2x^{2}=2x
Subtract 2x^{2} from both sides.
3x+6-2x^{2}-2x=0
Subtract 2x from both sides.
x+6-2x^{2}=0
Combine 3x and -2x to get x.
-2x^{2}+x+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{-1±\sqrt{1^{2}-4\left(-2\right)\times 6}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, 1 for b, and 6 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-1±\sqrt{1-4\left(-2\right)\times 6}}{2\left(-2\right)}
Square 1.
x=\frac{-1±\sqrt{1+8\times 6}}{2\left(-2\right)}
Multiply -4 times -2.
x=\frac{-1±\sqrt{1+48}}{2\left(-2\right)}
Multiply 8 times 6.
x=\frac{-1±\sqrt{49}}{2\left(-2\right)}
Add 1 to 48.
x=\frac{-1±7}{2\left(-2\right)}
Take the square root of 49.
x=\frac{-1±7}{-4}
Multiply 2 times -2.
x=\frac{6}{-4}
Now solve the equation x=\frac{-1±7}{-4} when ± is plus. Add -1 to 7.
x=-\frac{3}{2}
Reduce the fraction \frac{6}{-4} to lowest terms by extracting and canceling out 2.
x=-\frac{8}{-4}
Now solve the equation x=\frac{-1±7}{-4} when ± is minus. Subtract 7 from -1.
x=2
Divide -8 by -4.
x=-\frac{3}{2} x=2
The equation is now solved.
3\left(x+2\right)=x\left(x+1\right)\times 2
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 3x, the least common multiple of x,3.
3x+6=x\left(x+1\right)\times 2
Use the distributive property to multiply 3 by x+2.
3x+6=\left(x^{2}+x\right)\times 2
Use the distributive property to multiply x by x+1.
3x+6=2x^{2}+2x
Use the distributive property to multiply x^{2}+x by 2.
3x+6-2x^{2}=2x
Subtract 2x^{2} from both sides.
3x+6-2x^{2}-2x=0
Subtract 2x from both sides.
x+6-2x^{2}=0
Combine 3x and -2x to get x.
x-2x^{2}=-6
Subtract 6 from both sides. Anything subtracted from zero gives its negation.
-2x^{2}+x=-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{-2x^{2}+x}{-2}=-\frac{6}{-2}
Divide both sides by -2.
x^{2}+\frac{1}{-2}x=-\frac{6}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}-\frac{1}{2}x=-\frac{6}{-2}
Divide 1 by -2.
x^{2}-\frac{1}{2}x=3
Divide -6 by -2.
x^{2}-\frac{1}{2}x+\left(-\frac{1}{4}\right)^{2}=3+\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}=3+\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{49}{16}
Add 3 to \frac{1}{16}.
\left(x-\frac{1}{4}\right)^{2}=\frac{49}{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{49}{16}}
Take the square root of both sides of the equation.
x-\frac{1}{4}=\frac{7}{4} x-\frac{1}{4}=-\frac{7}{4}
Simplify.
x=2 x=-\frac{3}{2}
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}