已知x-2y=15,xy=-25,求 x²+4y²-1的值?

来源：学生作业帮助网编辑：六六作业网时间：2024/05/29 07:19:36

已知x-2y=15,xy=-25,求x²+4y²-1的值?已知x-2y=15,xy=-25,求x²+4y²-1的值?已知x-2y=15,xy=-25,求x&su

已知x-2y=15,xy=-25,求 x²+4y²-1的值?
已知x-2y=15,xy=-25,求 x²+4y²-1的值?

已知x-2y=15,xy=-25,求 x²+4y²-1的值?
x²+4y²-1
=(x-2y)²+4xy-1
把x-2y=15,xy=-25代入上式,得
x²+4y²-1
=(x-2y)²+4xy-1
=15²+4×(-25)-1
=225-100-1
=125-1
=124

324

已知x-2y=15，xy=-25
那么x²+4y²-1=(x-2y)²+4xy-1=15²+4*(-25)-1=124

x²+4y²-1=x²-4xy+(2y)²+4xy-1=(x-2y)²+4xy-1=15²+4(-25)-1=124

已知x-xy=8,xy-y=-9,求x+y-2xy的值已知x2+xy=12,xy+y2=15,求(x+y)2-(x+y)(x-y)的值已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy 已知:x>0,y>0,且x- 10√xy+25y=0,求2x+√xy+3y/x+√xy-y 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理. 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 已知:x-xy=40,xy-y=-20,求代数式x-y和x+y-2xy的值. 已知x-xy =21,xy-y=-12,分别求式子x-y与x-2xy +y 已知y=3xy+x,求代数式2x+3xy-2y/x-2xy-y的值已知x+y=3xy,求2x+2y-xy/x+y+2xy的值、已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值. 已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y) 已知x-y=3xy,求2x+3xy-2y/x-2xy-y 已知x-y=4xy,求2x+3xy-2y/x-2xy-y的值已知x-y=xy,求(2x-xy-2y)/(x-2xy-y)的值已知x-y=3xy,求2x-3xy-2y/x-2xy-y 已知X-XY-2Y=0求2X+3XY-Y/X-2XY+5Y 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!