Solve for x
x=\sqrt{7}+3\approx 5.645751311
x=3-\sqrt{7}\approx 0.354248689
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\left(x+1\right)\times 2+\left(x-2\right)\times 3=\left(x-2\right)\left(x+1\right)
Variable x cannot be equal to any of the values -1,2 since division by zero is not defined. Multiply both sides of the equation by \left(x-2\right)\left(x+1\right), the least common multiple of x-2,x+1.
2x+2+\left(x-2\right)\times 3=\left(x-2\right)\left(x+1\right)
Use the distributive property to multiply x+1 by 2.
2x+2+3x-6=\left(x-2\right)\left(x+1\right)
Use the distributive property to multiply x-2 by 3.
5x+2-6=\left(x-2\right)\left(x+1\right)
Combine 2x and 3x to get 5x.
5x-4=\left(x-2\right)\left(x+1\right)
Subtract 6 from 2 to get -4.
5x-4=x^{2}-x-2
Use the distributive property to multiply x-2 by x+1 and combine like terms.
5x-4-x^{2}=-x-2
Subtract x^{2} from both sides.
5x-4-x^{2}+x=-2
Add x to both sides.
6x-4-x^{2}=-2
Combine 5x and x to get 6x.
6x-4-x^{2}+2=0
Add 2 to both sides.
6x-2-x^{2}=0
Add -4 and 2 to get -2.
-x^{2}+6x-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{-6±\sqrt{6^{2}-4\left(-1\right)\left(-2\right)}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 6 for b, and -2 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-6±\sqrt{36-4\left(-1\right)\left(-2\right)}}{2\left(-1\right)}
Square 6.
x=\frac{-6±\sqrt{36+4\left(-2\right)}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{-6±\sqrt{36-8}}{2\left(-1\right)}
Multiply 4 times -2.
x=\frac{-6±\sqrt{28}}{2\left(-1\right)}
Add 36 to -8.
x=\frac{-6±2\sqrt{7}}{2\left(-1\right)}
Take the square root of 28.
x=\frac{-6±2\sqrt{7}}{-2}
Multiply 2 times -1.
x=\frac{2\sqrt{7}-6}{-2}
Now solve the equation x=\frac{-6±2\sqrt{7}}{-2} when ± is plus. Add -6 to 2\sqrt{7}.
x=3-\sqrt{7}
Divide -6+2\sqrt{7} by -2.
x=\frac{-2\sqrt{7}-6}{-2}
Now solve the equation x=\frac{-6±2\sqrt{7}}{-2} when ± is minus. Subtract 2\sqrt{7} from -6.
x=\sqrt{7}+3
Divide -6-2\sqrt{7} by -2.
x=3-\sqrt{7} x=\sqrt{7}+3
The equation is now solved.
\left(x+1\right)\times 2+\left(x-2\right)\times 3=\left(x-2\right)\left(x+1\right)
Variable x cannot be equal to any of the values -1,2 since division by zero is not defined. Multiply both sides of the equation by \left(x-2\right)\left(x+1\right), the least common multiple of x-2,x+1.
2x+2+\left(x-2\right)\times 3=\left(x-2\right)\left(x+1\right)
Use the distributive property to multiply x+1 by 2.
2x+2+3x-6=\left(x-2\right)\left(x+1\right)
Use the distributive property to multiply x-2 by 3.
5x+2-6=\left(x-2\right)\left(x+1\right)
Combine 2x and 3x to get 5x.
5x-4=\left(x-2\right)\left(x+1\right)
Subtract 6 from 2 to get -4.
5x-4=x^{2}-x-2
Use the distributive property to multiply x-2 by x+1 and combine like terms.
5x-4-x^{2}=-x-2
Subtract x^{2} from both sides.
5x-4-x^{2}+x=-2
Add x to both sides.
6x-4-x^{2}=-2
Combine 5x and x to get 6x.
6x-x^{2}=-2+4
Add 4 to both sides.
6x-x^{2}=2
Add -2 and 4 to get 2.
-x^{2}+6x=2
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{-x^{2}+6x}{-1}=\frac{2}{-1}
Divide both sides by -1.
x^{2}+\frac{6}{-1}x=\frac{2}{-1}
Dividing by -1 undoes the multiplication by -1.
x^{2}-6x=\frac{2}{-1}
Divide 6 by -1.
x^{2}-6x=-2
Divide 2 by -1.
x^{2}-6x+\left(-3\right)^{2}=-2+\left(-3\right)^{2}
Divide -6, the coefficient of the x term, by 2 to get -3. Then add the square of -3 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-6x+9=-2+9
Square -3.
x^{2}-6x+9=7
Add -2 to 9.
\left(x-3\right)^{2}=7
Factor x^{2}-6x+9. 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-3\right)^{2}}=\sqrt{7}
Take the square root of both sides of the equation.
x-3=\sqrt{7} x-3=-\sqrt{7}
Simplify.
x=\sqrt{7}+3 x=3-\sqrt{7}
Add 3 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}