# #2015_19 Application of Binomial Theorem

Algebra Level 5

If coefficients of ${ x }^{ 20 }$ in ${ (1-x+{ x }^{ 2 }) }^{ 20 }$ and in ${ (1+x-{ x }^{ 2 }) }^{ 20 }$ are respectively $a$ and $b$, then:

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