Solve for x
x=5
x = \frac{19}{5} = 3\frac{4}{5} = 3.8
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\left(x-4\right)\times 2-10x\left(x-4\right)=-2+\left(x-4\right)\left(-46\right)
Variable x cannot be equal to 4 since division by zero is not defined. Multiply both sides of the equation by x-4.
2x-8-10x\left(x-4\right)=-2+\left(x-4\right)\left(-46\right)
Use the distributive property to multiply x-4 by 2.
2x-8-10x^{2}+40x=-2+\left(x-4\right)\left(-46\right)
Use the distributive property to multiply -10x by x-4.
42x-8-10x^{2}=-2+\left(x-4\right)\left(-46\right)
Combine 2x and 40x to get 42x.
42x-8-10x^{2}=-2-46x+184
Use the distributive property to multiply x-4 by -46.
42x-8-10x^{2}=182-46x
Add -2 and 184 to get 182.
42x-8-10x^{2}-182=-46x
Subtract 182 from both sides.
42x-190-10x^{2}=-46x
Subtract 182 from -8 to get -190.
42x-190-10x^{2}+46x=0
Add 46x to both sides.
88x-190-10x^{2}=0
Combine 42x and 46x to get 88x.
-10x^{2}+88x-190=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{-88±\sqrt{88^{2}-4\left(-10\right)\left(-190\right)}}{2\left(-10\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -10 for a, 88 for b, and -190 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-88±\sqrt{7744-4\left(-10\right)\left(-190\right)}}{2\left(-10\right)}
Square 88.
x=\frac{-88±\sqrt{7744+40\left(-190\right)}}{2\left(-10\right)}
Multiply -4 times -10.
x=\frac{-88±\sqrt{7744-7600}}{2\left(-10\right)}
Multiply 40 times -190.
x=\frac{-88±\sqrt{144}}{2\left(-10\right)}
Add 7744 to -7600.
x=\frac{-88±12}{2\left(-10\right)}
Take the square root of 144.
x=\frac{-88±12}{-20}
Multiply 2 times -10.
x=-\frac{76}{-20}
Now solve the equation x=\frac{-88±12}{-20} when ± is plus. Add -88 to 12.
x=\frac{19}{5}
Reduce the fraction \frac{-76}{-20} to lowest terms by extracting and canceling out 4.
x=-\frac{100}{-20}
Now solve the equation x=\frac{-88±12}{-20} when ± is minus. Subtract 12 from -88.
x=5
Divide -100 by -20.
x=\frac{19}{5} x=5
The equation is now solved.
\left(x-4\right)\times 2-10x\left(x-4\right)=-2+\left(x-4\right)\left(-46\right)
Variable x cannot be equal to 4 since division by zero is not defined. Multiply both sides of the equation by x-4.
2x-8-10x\left(x-4\right)=-2+\left(x-4\right)\left(-46\right)
Use the distributive property to multiply x-4 by 2.
2x-8-10x^{2}+40x=-2+\left(x-4\right)\left(-46\right)
Use the distributive property to multiply -10x by x-4.
42x-8-10x^{2}=-2+\left(x-4\right)\left(-46\right)
Combine 2x and 40x to get 42x.
42x-8-10x^{2}=-2-46x+184
Use the distributive property to multiply x-4 by -46.
42x-8-10x^{2}=182-46x
Add -2 and 184 to get 182.
42x-8-10x^{2}+46x=182
Add 46x to both sides.
88x-8-10x^{2}=182
Combine 42x and 46x to get 88x.
88x-10x^{2}=182+8
Add 8 to both sides.
88x-10x^{2}=190
Add 182 and 8 to get 190.
-10x^{2}+88x=190
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{-10x^{2}+88x}{-10}=\frac{190}{-10}
Divide both sides by -10.
x^{2}+\frac{88}{-10}x=\frac{190}{-10}
Dividing by -10 undoes the multiplication by -10.
x^{2}-\frac{44}{5}x=\frac{190}{-10}
Reduce the fraction \frac{88}{-10} to lowest terms by extracting and canceling out 2.
x^{2}-\frac{44}{5}x=-19
Divide 190 by -10.
x^{2}-\frac{44}{5}x+\left(-\frac{22}{5}\right)^{2}=-19+\left(-\frac{22}{5}\right)^{2}
Divide -\frac{44}{5}, the coefficient of the x term, by 2 to get -\frac{22}{5}. Then add the square of -\frac{22}{5} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-\frac{44}{5}x+\frac{484}{25}=-19+\frac{484}{25}
Square -\frac{22}{5} by squaring both the numerator and the denominator of the fraction.
x^{2}-\frac{44}{5}x+\frac{484}{25}=\frac{9}{25}
Add -19 to \frac{484}{25}.
\left(x-\frac{22}{5}\right)^{2}=\frac{9}{25}
Factor x^{2}-\frac{44}{5}x+\frac{484}{25}. 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{22}{5}\right)^{2}}=\sqrt{\frac{9}{25}}
Take the square root of both sides of the equation.
x-\frac{22}{5}=\frac{3}{5} x-\frac{22}{5}=-\frac{3}{5}
Simplify.
x=5 x=\frac{19}{5}
Add \frac{22}{5} 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}