\(35)\) \(\left(3x+2\right)^2+\left(3x-2\right)^2-2\left(9x^2-4\right)\)
\(=\left(3x+2\right)^2-2\left[\left(3x\right)^2-2^2\right]+\left(3x-2\right)^2\)
\(=\left(3x+2\right)^2-2\left(3x+2\right)\left(3x-2\right)+\left(3x-2\right)^2\)
\(=\left(3x+2-3x+2\right)^2\)
\(=4^2=16\)
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\(\left(3x+2\right)^2+\left(3x-2\right)^2-2\left(9x^2-4\right)\)
\(=\left(3x+2\right)^2+\left(3x-2\right)^2-2\left(3x+2\right)\left(3x-2\right)\)
\(=\left[3x+2-\left(3x-2\right)\right]^2\)
\(=4^2=16\)
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