已知a=-1/8,b=2,求代数式(a+b/2)^2-(a-b/2)^2的值

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已知a=-1/8,b=2,求代数式(a+b/2)^2-(a-b/2)^2的值

已知a=-1/8,b=2,求代数式(a+b/2)^2-(a-b/2)^2的值
已知a=-1/8,b=2,求代数式(a+b/2)^2-(a-b/2)^2的值

已知a=-1/8,b=2,求代数式(a+b/2)^2-(a-b/2)^2的值
(a+b/2)^2-(a-b/2)^2
=(a+b/2-a+b/2)(a+b/2+a-b/2)
=b*2a
=2ab
=2*(-1/8)*2
=-1/2

(a+b/2)^2-(a-b/2)^2
=[(a+b/2)+(a-b/2)][(a+b/2)-(a-b/2)]
=(2a)*(b)
=2ab
=2*(-1/8)*2
=-1/2

(a+b/2)^2-(a-b/2)^2=ab=-1/8*2=-1/4

a=-1/8
b=2
(a+b/2)^2-(a-b/2)^2=(a+b/2+a-b/2)(a+b/2-a+b/2)=2a*b=2*(-1/8)*2=-1/2

(a+b/2)²-(a-b/2)²
=(a+b/2+a-b/2)(a+b/2-a+b/2)
=2ab=-1/2