Question

5(x-y)的立方-3(x-y)的平方+7(x-y)-3(x-y)的立方+(x-y)的平方-5,x-y=1/3.

Answer 1

5(x-y)的立方-3(x-y)的平方+7(x-y)-3(x-y)的立方+(x-y)的平方-5,

=2(x-y)³-2(x-y)²+7(x-y)-5

=2×1/27-2×1/9+7×1/3-5

=2/27-2/9+7/3-5

=2/27-6/27+63/27-135/27

=-76/27;

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