Evaluate
k\left(k+8\right)
Expand
k^{2}+8k
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k^{2}+8k+16-16
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(k+4\right)^{2}.
k^{2}+8k
Subtract 16 from 16 to get 0.
k^{2}+8k+16-16
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(k+4\right)^{2}.
k^{2}+8k
Subtract 16 from 16 to get 0.
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