3x-2y=40,x-4y=--50,则(x+y)^2-(2x-3y)^2的值是?
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3x-2y=40,x-4y=--50,则(x+y)^2-(2x-3y)^2的值是?
3x-2y=40,x-4y=--50,则(x+y)^2-(2x-3y)^2的值是?
3x-2y=40,x-4y=--50,则(x+y)^2-(2x-3y)^2的值是?
3x-2y=40
x-4y=-50
(x+y)^2-(2x-3y)^2
=[(x+y)+(2x-3y)][(x+y)-(2x-3y)]
=(x+y+2x-3y)(x+y-2x+3y)
=(3x-2y)(-x+4y)
=-(3x-2y)(x-4y)
=-40*(-50)
=2000
①-②得 2X+2Y=90 X+Y=45 ①+②得 4X-6Y=-10 2X-3Y=-5
接着不用我教了吧 (45-5)(45+5)=2000
x+y/3+x-y/2=6 4(x+y)-2(x-y)=40
(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
(x+y)(x+2y)(x+3y)(x+4y)=-40y的值为根号11
2x-y/x+y=4,则4x-2y/2x+2y+3x+3y/2x-y
若x+y=4,则多项式1/2(x+y)+4(x-y)-3(x-y)-3/2(x+y)-x+y值是()
3x-2y=40,x-4y=--50,则(x+y)^2-(2x-3y)^2的值是?
2(x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20
4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6
3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9
3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
(x+y)/2- x-y/2=6 3(x+y)=4(x-y)
4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2