计算或化简:(1)(-3)0+(+0.2)2009×(+5)2010(2)2(x+4)(x-4)(3)(x+2)2-(x+1)(x-1)

发布于2022-02-19 14:21:03

计算或化简:(1)(-3)0+(+0.2)2009×(+5)2010(2)2(x+4)(x-4)(3)(x+2)2-(x+1)(x-1)(4)先化简,再求值(m-2n)(m+2n)-(-m+n)2,其中m=12,n=-1.

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网友回答2022-02-19
(1)原式=1+(+0.2)2009×(+5)2009×(+5) =1+(0.2×5)2009×5 =1+5 =6; (2)原式=2(x2-16) =2x2-32; (3)原式=x2+4x+4-x2+1 =4x+5; (4)原式=4m2-n2-m2-n2+2mn =3m2-2n2+2mn, ∵m= 1 2 ,n=-1, ∴原式=3m2-2n2+2mn =3×( 1 2 )2-2×(-1)2+2× 1 2 ×(-1) = 3 4 -2-1 =- 9 4 .

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