Solve for a_320
a_{320}=8a\left(50-a\right)
Solve for a (complex solution)
a=\frac{\sqrt{10000-2a_{320}}}{4}+25
a=-\frac{\sqrt{10000-2a_{320}}}{4}+25
Solve for a
a=\frac{\sqrt{10000-2a_{320}}}{4}+25
a=-\frac{\sqrt{10000-2a_{320}}}{4}+25\text{, }a_{320}\leq 5000
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10000=\left(100-4a\right)^{2}+2a_{320}
Calculate 100 to the power of 2 and get 10000.
10000=10000-800a+16a^{2}+2a_{320}
Use binomial theorem \left(p-q\right)^{2}=p^{2}-2pq+q^{2} to expand \left(100-4a\right)^{2}.
10000-800a+16a^{2}+2a_{320}=10000
Swap sides so that all variable terms are on the left hand side.
-800a+16a^{2}+2a_{320}=10000-10000
Subtract 10000 from both sides.
-800a+16a^{2}+2a_{320}=0
Subtract 10000 from 10000 to get 0.
16a^{2}+2a_{320}=800a
Add 800a to both sides. Anything plus zero gives itself.
2a_{320}=800a-16a^{2}
Subtract 16a^{2} from both sides.
\frac{2a_{320}}{2}=\frac{16a\left(50-a\right)}{2}
Divide both sides by 2.
a_{320}=\frac{16a\left(50-a\right)}{2}
Dividing by 2 undoes the multiplication by 2.
a_{320}=8a\left(50-a\right)
Divide 16a\left(50-a\right) by 2.
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