8x 7y 14*(10-x-y)=101
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x^2+y^2-8x-6y+21=0配方,有:x^2-8x+16+y^2-6y+9=4(x-4)^2+(y-3)^2=4这是一个以(4,3)为圆心,2为半径的圆令x-4=2sinay-3=2cosa(
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=4x-2y-z-5x[6y-(x+y)]+x-(3y-10z)=4x-2y-z-30xy+5x²+5xy+x-3
二式乘4得三式,三式减一式得:17X=14得X=14/17将X代入一式,得Y=16/17
2y-7x=8①3x-8y-10=0②①*4+②,-28x+3x-10=32,x=-42/25代入①,2y-7*(-42/25)=8,y=-47/25
(4.5*10^5)(2*10^3)(3*10^4)=(4.5×2×3)×10^(5+3+4)=27×10¹²=2.7×10¹³2x^2y(-8y^2)+4x^
-3(2x-y)-{7x-[6x+2y-(10x-8y)]-x-2(3x-4y)}=-6x+3y-7x+(6x+2y-10x+8y)+x+6x-8y=-13x+3y-4x+10y+7x-8y=-10x
2x-7y=8①3x-8y=10②①乘3得到6x-21y=24③②乘2得到6x-16y=20④③-④得-5y=4y=-5分之4将y=-5分之4代入③得x=5分之6希望对你有帮助~望采纳,O(∩_∩)O
2x+y+x=10(1)x+2y+z=-6(2)x+y+2z=8(3)(1)+(2)+(3)4x+4y+4z=12x+y+z=3(4)(1)-(4),x=7(2)-(4),y=-9(3)-(4),z=
1、3y=2x①3x+4y+805=0②由①得x=1.5y,带入②4.5y+4y=-805y=-1610/17x=-2415/17……再问:再解一道(a+b-c)^3x(c-b-a)^2(-a-b+c
2x+y+z=10(1)x+2y+z=-6(2)x+y+z=8(3)(2)-(3):y=-14(4)(1)-(2):x-y=16(5)把(4)代入(5):x+14=16x=2(6)把(4)和(6)代入
-8(2x-y)-{7x-[6x+2y-(10x-8y)]}=-16x+8y-[7x-(6x+2y-10x+8y)]=-16x+8y-(7x-6x-2y+10x-8y)=-16x+8y-7x+6x+2
x^2+y^2-8x-10y+41=0x^2-8x+16+y^2-10y+25=0(x-4)^2+(y-5)^2=0所以x=4,y=5x/y+y/x=4/5+5/4=0.8+1.25=2.05
x^2+y^2-8x+10y+41=0(x-4)^2+(y+5)^2=0x=4,y=-5x+y=-1(x+y)^2013=-1
(X+2)(X+5)(X-4)(X+2)(y-3)(y-4)(x+9)(x-2)
当2x+y>0时就变为3x+y=10,x-2y=8解得x=4,y=-2满足2x+y>0当2x+y<0时变为-x-y=10,x-2y=8y=-6,x=-4满足2x+y<0∴两组解为x=4,y=-2或x=
-3(2x-y)-{7x-〔6x+2y-(10x-8y)〕-x-2(3x-4y)}=-6x+3y-{7x-6x-2y+10x-8y-x-6x+8y}=-6x+3y-(4x-2y)=-10x+5y由(x
-3(2x-y)-{7x-〔6x+2x-(10x-8y)〕-x-2(3x-4y)}=-6x+3y-{7x-〔8x-10x+8y)〕-x-6x+8y}=-6x+3y-{7x-〔-2x+8y)〕-7x+8
等于.-3y-10x
什么意思?再问:tangram_guid_1358503626031再答:1:2x+3y=7,3x-5y=1;x=2y=12:3x+5y=5,3x-4y=23;x=5y=-23:3x+5y=5,3x-