1、2a+5b与4a-4b的一半差是多少?2、一个多项式与x²-2X+1的和是3x²+5x-2,求这个多项式3、A=-1/2x²+xy-1.B=1/3x²y+3xy+2/3,求A-B,和2A-3B差.4、已知a²+ab=4,b²+ab=-1,求a²+2ab²+b²和a&su
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![1、2a+5b与4a-4b的一半差是多少?2、一个多项式与x²-2X+1的和是3x²+5x-2,求这个多项式3、A=-1/2x²+xy-1.B=1/3x²y+3xy+2/3,求A-B,和2A-3B差.4、已知a²+ab=4,b²+ab=-1,求a²+2ab²+b²和a&su](/uploads/image/z/655272-0-2.jpg?t=1%E3%80%812a%2B5b%E4%B8%8E4a-4b%E7%9A%84%E4%B8%80%E5%8D%8A%E5%B7%AE%E6%98%AF%E5%A4%9A%E5%B0%91%3F2%E3%80%81%E4%B8%80%E4%B8%AA%E5%A4%9A%E9%A1%B9%E5%BC%8F%E4%B8%8Ex%26sup2%3B-2X%2B1%E7%9A%84%E5%92%8C%E6%98%AF3x%26sup2%3B%2B5x-2%2C%E6%B1%82%E8%BF%99%E4%B8%AA%E5%A4%9A%E9%A1%B9%E5%BC%8F3%E3%80%81A%3D-1%2F2x%26sup2%3B%2Bxy-1.B%3D1%2F3x%26sup2%3By%2B3xy%2B2%2F3%2C%E6%B1%82A-B%2C%E5%92%8C2A-3B%E5%B7%AE.4%E3%80%81%E5%B7%B2%E7%9F%A5a%26sup2%3B%2Bab%3D4%2Cb%26sup2%3B%2Bab%3D-1%2C%E6%B1%82a%26sup2%3B%2B2ab%26sup2%3B%2Bb%26sup2%3B%E5%92%8Ca%26su)
1、2a+5b与4a-4b的一半差是多少?2、一个多项式与x²-2X+1的和是3x²+5x-2,求这个多项式3、A=-1/2x²+xy-1.B=1/3x²y+3xy+2/3,求A-B,和2A-3B差.4、已知a²+ab=4,b²+ab=-1,求a²+2ab²+b²和a&su
1、2a+5b与4a-4b的一半差是多少?
2、一个多项式与x²-2X+1的和是3x²+5x-2,求这个多项式
3、A=-1/2x²+xy-1.B=1/3x²y+3xy+2/3,求A-B,和2A-3B差.
4、已知a²+ab=4,b²+ab=-1,求a²+2ab²+b²和a²-b²的值.
1、2a+5b与4a-4b的一半差是多少?2、一个多项式与x²-2X+1的和是3x²+5x-2,求这个多项式3、A=-1/2x²+xy-1.B=1/3x²y+3xy+2/3,求A-B,和2A-3B差.4、已知a²+ab=4,b²+ab=-1,求a²+2ab²+b²和a&su
1.2a+5b-1/2(4a-4b)
=2a+5b-2a+2b
=7b
2.这个多项式=(3x²+5x-2)-(x²-2x+1)
=3x²+5x-2-x²+2x-1
=2x²+7x-3
3.A-B=(-1/2x²+xy-1)-(1/3x²y+3xy+2/3)
=-5/6x²-2xy-5/3
2A-3B=2(-1/2x²+xy-1)-3(1/3x²y+3xy+2/3)
=-2x²-7xy-4
4.a²+2ab²+b²
=a²+ab+b²+ab
=4-1
=3
a²-b²
=a²+ab-ab-b²
=(a²+ab)-(b²+ab)
=4+1
=5
7b;
2x²+7x-3;
-1/2x²-2xy-1/3x²y-1/3 -x²-x²y-4xy-4;
3 5
1,7b
2,2x²+7x-3
3,-1/2x²-2xy-1/3x²y-5/3 -7xy-4-x²-x²y
4,3 5
2a+5b-1/2(4a-4b)=7b
3x2+5x-2-(x2-2X+1)=2x2+9x-3
3,直接求
4,a2+2ab+b2=3
a2-b2=5
a= b= 直接求