Solve for k
k = \frac{19}{6} = 3\frac{1}{6} \approx 3.166666667
k = \frac{8}{3} = 2\frac{2}{3} \approx 2.666666667
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2+\left(3k-10\right)\times 5+\left(3k-10\right)^{2}\times 2=0
Variable k cannot be equal to \frac{10}{3} since division by zero is not defined. Multiply both sides of the equation by \left(3k-10\right)^{2}, the least common multiple of \left(3k-10\right)^{2},3k-10.
2+15k-50+\left(3k-10\right)^{2}\times 2=0
Use the distributive property to multiply 3k-10 by 5.
-48+15k+\left(3k-10\right)^{2}\times 2=0
Subtract 50 from 2 to get -48.
-48+15k+\left(9k^{2}-60k+100\right)\times 2=0
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(3k-10\right)^{2}.
-48+15k+18k^{2}-120k+200=0
Use the distributive property to multiply 9k^{2}-60k+100 by 2.
-48-105k+18k^{2}+200=0
Combine 15k and -120k to get -105k.
152-105k+18k^{2}=0
Add -48 and 200 to get 152.
18k^{2}-105k+152=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.
k=\frac{-\left(-105\right)±\sqrt{\left(-105\right)^{2}-4\times 18\times 152}}{2\times 18}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 18 for a, -105 for b, and 152 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
k=\frac{-\left(-105\right)±\sqrt{11025-4\times 18\times 152}}{2\times 18}
Square -105.
k=\frac{-\left(-105\right)±\sqrt{11025-72\times 152}}{2\times 18}
Multiply -4 times 18.
k=\frac{-\left(-105\right)±\sqrt{11025-10944}}{2\times 18}
Multiply -72 times 152.
k=\frac{-\left(-105\right)±\sqrt{81}}{2\times 18}
Add 11025 to -10944.
k=\frac{-\left(-105\right)±9}{2\times 18}
Take the square root of 81.
k=\frac{105±9}{2\times 18}
The opposite of -105 is 105.
k=\frac{105±9}{36}
Multiply 2 times 18.
k=\frac{114}{36}
Now solve the equation k=\frac{105±9}{36} when ± is plus. Add 105 to 9.
k=\frac{19}{6}
Reduce the fraction \frac{114}{36} to lowest terms by extracting and canceling out 6.
k=\frac{96}{36}
Now solve the equation k=\frac{105±9}{36} when ± is minus. Subtract 9 from 105.
k=\frac{8}{3}
Reduce the fraction \frac{96}{36} to lowest terms by extracting and canceling out 12.
k=\frac{19}{6} k=\frac{8}{3}
The equation is now solved.
2+\left(3k-10\right)\times 5+\left(3k-10\right)^{2}\times 2=0
Variable k cannot be equal to \frac{10}{3} since division by zero is not defined. Multiply both sides of the equation by \left(3k-10\right)^{2}, the least common multiple of \left(3k-10\right)^{2},3k-10.
2+15k-50+\left(3k-10\right)^{2}\times 2=0
Use the distributive property to multiply 3k-10 by 5.
-48+15k+\left(3k-10\right)^{2}\times 2=0
Subtract 50 from 2 to get -48.
-48+15k+\left(9k^{2}-60k+100\right)\times 2=0
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(3k-10\right)^{2}.
-48+15k+18k^{2}-120k+200=0
Use the distributive property to multiply 9k^{2}-60k+100 by 2.
-48-105k+18k^{2}+200=0
Combine 15k and -120k to get -105k.
152-105k+18k^{2}=0
Add -48 and 200 to get 152.
-105k+18k^{2}=-152
Subtract 152 from both sides. Anything subtracted from zero gives its negation.
18k^{2}-105k=-152
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{18k^{2}-105k}{18}=-\frac{152}{18}
Divide both sides by 18.
k^{2}+\left(-\frac{105}{18}\right)k=-\frac{152}{18}
Dividing by 18 undoes the multiplication by 18.
k^{2}-\frac{35}{6}k=-\frac{152}{18}
Reduce the fraction \frac{-105}{18} to lowest terms by extracting and canceling out 3.
k^{2}-\frac{35}{6}k=-\frac{76}{9}
Reduce the fraction \frac{-152}{18} to lowest terms by extracting and canceling out 2.
k^{2}-\frac{35}{6}k+\left(-\frac{35}{12}\right)^{2}=-\frac{76}{9}+\left(-\frac{35}{12}\right)^{2}
Divide -\frac{35}{6}, the coefficient of the x term, by 2 to get -\frac{35}{12}. Then add the square of -\frac{35}{12} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
k^{2}-\frac{35}{6}k+\frac{1225}{144}=-\frac{76}{9}+\frac{1225}{144}
Square -\frac{35}{12} by squaring both the numerator and the denominator of the fraction.
k^{2}-\frac{35}{6}k+\frac{1225}{144}=\frac{1}{16}
Add -\frac{76}{9} to \frac{1225}{144} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
\left(k-\frac{35}{12}\right)^{2}=\frac{1}{16}
Factor k^{2}-\frac{35}{6}k+\frac{1225}{144}. 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(k-\frac{35}{12}\right)^{2}}=\sqrt{\frac{1}{16}}
Take the square root of both sides of the equation.
k-\frac{35}{12}=\frac{1}{4} k-\frac{35}{12}=-\frac{1}{4}
Simplify.
k=\frac{19}{6} k=\frac{8}{3}
Add \frac{35}{12} to both sides of the equation.
Examples
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{ 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}