加法:$20 x^{2} y^{2} z$ 和 $-10 x^{2} y^{2} z$
解答
加 $20 x^2 y^2 z$ 和 $- 10 x^2 y^2 z$ 意味着
$20 x^{2} y^{2} z + (− 10 x^{2} y^{2} z)$
= $20 x^{2} y^{2 }z − 10 x^{2} y^{2} z$
= $10 x^{2} y^{2} z$ 因为它们是同类项
所以 $20 x^{2} y^{2} z + (− 10 x^{2} y^{2} z) = 10 x^{2} y^{2} $z
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