Solve for k
k=2
k=32
Share
Copied to clipboard
\left(k-8\right)\left(k-8\right)=3k\times 6
Variable k cannot be equal to any of the values 0,8 since division by zero is not defined. Multiply both sides of the equation by 3k\left(k-8\right), the least common multiple of 3k,k-8.
\left(k-8\right)^{2}=3k\times 6
Multiply k-8 and k-8 to get \left(k-8\right)^{2}.
k^{2}-16k+64=3k\times 6
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(k-8\right)^{2}.
k^{2}-16k+64=18k
Multiply 3 and 6 to get 18.
k^{2}-16k+64-18k=0
Subtract 18k from both sides.
k^{2}-34k+64=0
Combine -16k and -18k to get -34k.
a+b=-34 ab=64
To solve the equation, factor k^{2}-34k+64 using formula k^{2}+\left(a+b\right)k+ab=\left(k+a\right)\left(k+b\right). To find a and b, set up a system to be solved.
-1,-64 -2,-32 -4,-16 -8,-8
Since ab is positive, a and b have the same sign. Since a+b is negative, a and b are both negative. List all such integer pairs that give product 64.
-1-64=-65 -2-32=-34 -4-16=-20 -8-8=-16
Calculate the sum for each pair.
a=-32 b=-2
The solution is the pair that gives sum -34.
\left(k-32\right)\left(k-2\right)
Rewrite factored expression \left(k+a\right)\left(k+b\right) using the obtained values.
k=32 k=2
To find equation solutions, solve k-32=0 and k-2=0.
\left(k-8\right)\left(k-8\right)=3k\times 6
Variable k cannot be equal to any of the values 0,8 since division by zero is not defined. Multiply both sides of the equation by 3k\left(k-8\right), the least common multiple of 3k,k-8.
\left(k-8\right)^{2}=3k\times 6
Multiply k-8 and k-8 to get \left(k-8\right)^{2}.
k^{2}-16k+64=3k\times 6
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(k-8\right)^{2}.
k^{2}-16k+64=18k
Multiply 3 and 6 to get 18.
k^{2}-16k+64-18k=0
Subtract 18k from both sides.
k^{2}-34k+64=0
Combine -16k and -18k to get -34k.
a+b=-34 ab=1\times 64=64
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as k^{2}+ak+bk+64. To find a and b, set up a system to be solved.
-1,-64 -2,-32 -4,-16 -8,-8
Since ab is positive, a and b have the same sign. Since a+b is negative, a and b are both negative. List all such integer pairs that give product 64.
-1-64=-65 -2-32=-34 -4-16=-20 -8-8=-16
Calculate the sum for each pair.
a=-32 b=-2
The solution is the pair that gives sum -34.
\left(k^{2}-32k\right)+\left(-2k+64\right)
Rewrite k^{2}-34k+64 as \left(k^{2}-32k\right)+\left(-2k+64\right).
k\left(k-32\right)-2\left(k-32\right)
Factor out k in the first and -2 in the second group.
\left(k-32\right)\left(k-2\right)
Factor out common term k-32 by using distributive property.
k=32 k=2
To find equation solutions, solve k-32=0 and k-2=0.
\left(k-8\right)\left(k-8\right)=3k\times 6
Variable k cannot be equal to any of the values 0,8 since division by zero is not defined. Multiply both sides of the equation by 3k\left(k-8\right), the least common multiple of 3k,k-8.
\left(k-8\right)^{2}=3k\times 6
Multiply k-8 and k-8 to get \left(k-8\right)^{2}.
k^{2}-16k+64=3k\times 6
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(k-8\right)^{2}.
k^{2}-16k+64=18k
Multiply 3 and 6 to get 18.
k^{2}-16k+64-18k=0
Subtract 18k from both sides.
k^{2}-34k+64=0
Combine -16k and -18k to get -34k.
k=\frac{-\left(-34\right)±\sqrt{\left(-34\right)^{2}-4\times 64}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -34 for b, and 64 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
k=\frac{-\left(-34\right)±\sqrt{1156-4\times 64}}{2}
Square -34.
k=\frac{-\left(-34\right)±\sqrt{1156-256}}{2}
Multiply -4 times 64.
k=\frac{-\left(-34\right)±\sqrt{900}}{2}
Add 1156 to -256.
k=\frac{-\left(-34\right)±30}{2}
Take the square root of 900.
k=\frac{34±30}{2}
The opposite of -34 is 34.
k=\frac{64}{2}
Now solve the equation k=\frac{34±30}{2} when ± is plus. Add 34 to 30.
k=32
Divide 64 by 2.
k=\frac{4}{2}
Now solve the equation k=\frac{34±30}{2} when ± is minus. Subtract 30 from 34.
k=2
Divide 4 by 2.
k=32 k=2
The equation is now solved.
\left(k-8\right)\left(k-8\right)=3k\times 6
Variable k cannot be equal to any of the values 0,8 since division by zero is not defined. Multiply both sides of the equation by 3k\left(k-8\right), the least common multiple of 3k,k-8.
\left(k-8\right)^{2}=3k\times 6
Multiply k-8 and k-8 to get \left(k-8\right)^{2}.
k^{2}-16k+64=3k\times 6
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(k-8\right)^{2}.
k^{2}-16k+64=18k
Multiply 3 and 6 to get 18.
k^{2}-16k+64-18k=0
Subtract 18k from both sides.
k^{2}-34k+64=0
Combine -16k and -18k to get -34k.
k^{2}-34k=-64
Subtract 64 from both sides. Anything subtracted from zero gives its negation.
k^{2}-34k+\left(-17\right)^{2}=-64+\left(-17\right)^{2}
Divide -34, the coefficient of the x term, by 2 to get -17. Then add the square of -17 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
k^{2}-34k+289=-64+289
Square -17.
k^{2}-34k+289=225
Add -64 to 289.
\left(k-17\right)^{2}=225
Factor k^{2}-34k+289. 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-17\right)^{2}}=\sqrt{225}
Take the square root of both sides of the equation.
k-17=15 k-17=-15
Simplify.
k=32 k=2
Add 17 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}