Solve for N
N=\frac{\left(9-x\right)^{2}+8}{4}
Solve for x (complex solution)
x=2\sqrt{N-2}+9
x=-2\sqrt{N-2}+9
Solve for x
x=2\sqrt{N-2}+9
x=-2\sqrt{N-2}+9\text{, }N\geq 2
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4N=81-18x+x^{2}+\left(2\sqrt{2}\right)^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(9-x\right)^{2}.
4N=81-18x+x^{2}+2^{2}\left(\sqrt{2}\right)^{2}
Expand \left(2\sqrt{2}\right)^{2}.
4N=81-18x+x^{2}+4\left(\sqrt{2}\right)^{2}
Calculate 2 to the power of 2 and get 4.
4N=81-18x+x^{2}+4\times 2
The square of \sqrt{2} is 2.
4N=81-18x+x^{2}+8
Multiply 4 and 2 to get 8.
4N=89-18x+x^{2}
Add 81 and 8 to get 89.
4N=x^{2}-18x+89
The equation is in standard form.
\frac{4N}{4}=\frac{x^{2}-18x+89}{4}
Divide both sides by 4.
N=\frac{x^{2}-18x+89}{4}
Dividing by 4 undoes the multiplication by 4.
N=\frac{x^{2}}{4}-\frac{9x}{2}+\frac{89}{4}
Divide 89-18x+x^{2} by 4.
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Limits
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