Question

有这样一道题当a=2b=负1/3求代数式7a^3-6a^3b+3a^2b+3a^3+6a^3b-3a^2b-10a^3+

Answer 1

7a^3-6a^3b+3a^2b+3a^3+6a^3b-3a^2b-10a^3+3

=(7a^3+3a^3-10a^3)+(-6a^3b+6a^3b)+(3a^2b-3a^2b)+3

=0+0+0+3

=3

题中给出的条件a=2,b-负1/3是多余的,他的说法有道理.