\(=1^2-\left(2x\right)^2-\left(x^2-2^2\right)=1-\left(2x\right)^2-x^2+2^2=\left(1-x^2\right)-\left(\left(2x\right)^2-2^2\right)\)
\(=\left(1+x\right)\left(1-x\right)-\left(2x+2\right)\left(2x-2\right)\)
\(=\left(x+1\right)\left(1-x\right)-2\left(x+1\right)2\left(x-1\right)=\left(x+1\right)\left(1-x\right)+4\left(x+1\right)\left(1-x\right)\)
\(=5\left(x+1\right)\left(1-x\right)\)
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