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1.计算 (1)(0.25x-4分之1)(0.25x+0.25) (2)(-7x^3y-3b^2(7x^y-3b^2) (3) (3x-y)(3x+y)
1.计算
(1)(0.25x-4分之1)(0.25x+0.25) (2)(-7x^3y-3b^2(7x^y-3b^2) (3) (3x-y)(3x+y)+y(x+y) (4)(x-2)(16+x^4)(2+x)(4+x^2)
2.用简便的方法计算
(1) 40又3分之2×39又3分之1 (2)3×5×17×(2^8+1)
人气:262 ℃ 时间:2020-04-29 08:19:56
解答
1、(1)=(0.25x-0.25)(0.25x+0.25)=(0.25x)^2-0.25^2
(2)=-(7x^3y+3b^2)(7x^y-3b^2)=-49x^6y^2+9b^4
(3)= 9x^2-y^2+y(x+y)= 9x^2+yx
(4)=(x^2-4)(16+x^4)(2+x)(4+x^2)=(x^4-16)(16+x^4)=x^8-256
2、(1)=40+1/3+2/3+39=40+1+39=40+40=80
(2)=3×5×17×[(2^2)^4+1]=3×5×17×[(4^2)^2+1]=3×5×17×(16^2+1)=3×5×17×255
=255×255=255^2
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