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苏科版七年级上册数学书习题3.5答案

时间:2016-05-03 来源:书通网 共计2题

习题3.5第1题答案

(1)4a-2(b-3c)

=4a-2b+6c  

(2)-5a+(4x-6)/2

=-5a+2x-3

(3)3x+[4y-(7z+3)]

=3x+(4y-7z-3)

=3x+4y-7z-3 

(4)-3a3-[2x2-(5x+1)]

=-3a3-(2x2-5x-1)

=-3a3-2x2+5x+1

习题3.5第2题答案

(1)(8x-5y)-(4x-9y)

=8x-5y-4x+9y

=4x+4y  

(2)x-(2x-y)+(3x-2y)

=x-2x+y+3x-2y

=2x-y 

(3)2(x+y)+(-5x+2y)

=2x+2y-5x+2y

=4y-3x 

(4)(3a2-b2)-3(a2-2b2

=3a2-b2-3a2+6b2

=5b2

(5)-2(-3xy+2z)+3(-2xy-5x)

=6xy-4z-6xy-15x

=-4z-15x

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