Solve for n
n=3\sqrt{10}\approx 9.486832981
n=-3\sqrt{10}\approx -9.486832981
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n-\frac{90}{n}=0
Subtract \frac{90}{n} from both sides.
\frac{nn}{n}-\frac{90}{n}=0
To add or subtract expressions, expand them to make their denominators the same. Multiply n times \frac{n}{n}.
\frac{nn-90}{n}=0
Since \frac{nn}{n} and \frac{90}{n} have the same denominator, subtract them by subtracting their numerators.
\frac{n^{2}-90}{n}=0
Do the multiplications in nn-90.
n^{2}-90=0
Variable n cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by n.
n^{2}=90
Add 90 to both sides. Anything plus zero gives itself.
n=3\sqrt{10} n=-3\sqrt{10}
Take the square root of both sides of the equation.
n-\frac{90}{n}=0
Subtract \frac{90}{n} from both sides.
\frac{nn}{n}-\frac{90}{n}=0
To add or subtract expressions, expand them to make their denominators the same. Multiply n times \frac{n}{n}.
\frac{nn-90}{n}=0
Since \frac{nn}{n} and \frac{90}{n} have the same denominator, subtract them by subtracting their numerators.
\frac{n^{2}-90}{n}=0
Do the multiplications in nn-90.
n^{2}-90=0
Variable n cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by n.
n=\frac{0±\sqrt{0^{2}-4\left(-90\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -90 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
n=\frac{0±\sqrt{-4\left(-90\right)}}{2}
Square 0.
n=\frac{0±\sqrt{360}}{2}
Multiply -4 times -90.
n=\frac{0±6\sqrt{10}}{2}
Take the square root of 360.
n=3\sqrt{10}
Now solve the equation n=\frac{0±6\sqrt{10}}{2} when ± is plus.
n=-3\sqrt{10}
Now solve the equation n=\frac{0±6\sqrt{10}}{2} when ± is minus.
n=3\sqrt{10} n=-3\sqrt{10}
The equation is now solved.
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}