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