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已知整式x^2的值是1/4,y^2的值是4,则(5x^2y+5xy...

(5x^2y+5xy-7x)-(4x^y+5xy-7x) =5x^2y+5xy-7x-4x^y-5xy+7x =5x^2y-4x^y ∵y²=4, ∴y=2或-2, 当y=2时,x^y=x²=1/4, 原式=5*(1/4)*2-4*(1/4)=5/2-1=3/2 当y=-2时,x^y=4, 原式=5*(1/4)*(-2)-4*4=-5/2-16=-37/2

依题意得:(5x2y+5xy-7x)-(4x2y+5xy-7x)=5x2y+5xy-7x-4x2y-5xy+7x=x2y∵6x-1=2,y2-y=2,∴x=12,y=2或y=-1.∴原式=?14或12.故选C.

6x-1=2 x=1/2 y²-y=0 y=0 或者1 (5x的平方y加5xy减7x)减(4X的平方y加5xy减7x) =5x²y+5xy-7x-4x²y-5xy+7x =x²y =0 或者1/4

根据题意得到 设另一个因式为x+by-3 (x+y-2)(x+by-3) =x^2+bxy-3x+xy+by^2-3y-2x-2by+6 =x^2+(b+1)xy+by^2-5x-(3+2b)y+6 所以b+1=a,3+2b=1 所以a=0,b=-1 a+b=-1

1.3ab-4ab+8ab-7ab+ab=______. 2.7x-(5x-5y)-y=______. 3.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______. 4.-7x2+6x+13x2-4x-5x2=______. 5.2y+(-2y+5)-(3y+2)=______. 6.(2x2-3xy+4y2)+(x2+2xy-3y2)=______. 7.2a-(3a-2b+2)+(3a-4b-1)...

1.3ab-4ab+8ab-7ab+ab=______.2.7x-(5x-5y)-y=______.3.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______.4.-7x2+6x+13x2-4x-5x2=______.5.2y+(-2y+5)-(3y+2)=______.6.(2x2-3xy+4y2)+(x2+2xy-3y2)=______.7.2a-(3a-2b+2)+(3a-4b-1)=_____...

1.3ab-4ab+8ab-7ab+ab=______. 2.7x-(5x-5y)-y=______. 3.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______. 4.-7x2+6x+13x2-4x-5x2=______. 5.2y+(-2y+5)-(3y+2)=______. 6.(2x2-3xy+4y2)+(x2+2xy-3y2)=______. 7.2a-(3a-2b+2)+(3a-4b-1)=______. 8.-6...

C

根据题意得:5x+14+5(x-14)=0,去括号得:5x+14+5x-54=0,即10x-1=0,解得:x=110.故答案为:110

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