(1/2a+1/3b)(1/3b-1/2a)-(1/3b-1/2a)^2+(-1/3b-1/2a)^2 其中a=1/2 b=-1/_数学解答

(1/2a+1/3b)(1/3b-1/2a)-(1/3b-1/2a)^2+(-1/3b-1/2a)^2 其中a=1/2 b=-1/3
先化简后求值

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解答

(1/2a+1/3b)(1/3b-1/2a)-(1/3b-1/2a)^2+(-1/3b-1/2a)^2 =(1/3b+1/2a)(1/3b-1/2a)+(1/3b+1/2a)^2 -(1/3b-1/2a)^2=(1/3b+1/2a)(1/3b-1/2a)+(1/3b+1/2a +1/3b-1/2a)(1/3b+1/2a -1/3b+1/2a)=(1/3b)²-(1/2a)²+(...