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18x^{2}+8y^{2}
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18x^{2}+8y^{2}
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9x^{2}+12xy+4y^{2}+\left(3x-2y\right)^{2}
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(3x+2y\right)^{2}.
9x^{2}+12xy+4y^{2}+9x^{2}-12xy+4y^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(3x-2y\right)^{2}.
18x^{2}+12xy+4y^{2}-12xy+4y^{2}
Combine 9x^{2} and 9x^{2} to get 18x^{2}.
18x^{2}+4y^{2}+4y^{2}
Combine 12xy and -12xy to get 0.
18x^{2}+8y^{2}
Combine 4y^{2} and 4y^{2} to get 8y^{2}.
9x^{2}+12xy+4y^{2}+\left(3x-2y\right)^{2}
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(3x+2y\right)^{2}.
9x^{2}+12xy+4y^{2}+9x^{2}-12xy+4y^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(3x-2y\right)^{2}.
18x^{2}+12xy+4y^{2}-12xy+4y^{2}
Combine 9x^{2} and 9x^{2} to get 18x^{2}.
18x^{2}+4y^{2}+4y^{2}
Combine 12xy and -12xy to get 0.
18x^{2}+8y^{2}
Combine 4y^{2} and 4y^{2} to get 8y^{2}.
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