(0.7X+0.6Y)/(X+Y)=66% [0.7(X-5)+0.6(y-5)]/(x+y-10)=66.25 % 奖
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(0.7X+0.6Y)/(X+Y)=66% [0.7(X-5)+0.6(y-5)]/(x+y-10)=66.25 % 奖励50000000000分
70%x+60%y=66%(x+y)
0.7x+0.6y=0.66x+0.66y
0.04x=0.06y
4x=6y
x=1.5y
70%(x-5)+60%(y-5)=66.25%(x+y-10)
0.7x-3.5+0.6y=0.6625x+0.6625y-6.625
0.0375x-0.0625y=-3.125
3/80x-5/80y=-25/8
0.3x-0.5y=-25
将x=1.5y代入上式,得
0.3*1.5y-0.5y=-25
0.45y-0.5y=-25
0.05y=25
y=500
x=1.5y=1.5*500=750
0.7x+0.6y=0.66x+0.66y
0.04x=0.06y
4x=6y
x=1.5y
70%(x-5)+60%(y-5)=66.25%(x+y-10)
0.7x-3.5+0.6y=0.6625x+0.6625y-6.625
0.0375x-0.0625y=-3.125
3/80x-5/80y=-25/8
0.3x-0.5y=-25
将x=1.5y代入上式,得
0.3*1.5y-0.5y=-25
0.45y-0.5y=-25
0.05y=25
y=500
x=1.5y=1.5*500=750
x+y=5; x^y+y^x=17
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
解方程组:2/(x+y)+5/(x-y)=18 9/(x+y)-10/(y-x)=66
解方程组:2/(x+y)+5/(x-y)=18 9/(x+y)-10/(y-x)=66
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
Y={X (-5
(5x+3y)(3y-5x)-(4x-y)(4y+x)=
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy)