y=10*20-x,y的各个位上的数字之和等于160
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![y=10*20-x,y的各个位上的数字之和等于160](/uploads/image/f/908217-9-7.jpg?t=y%3D10%2A20-x%2Cy%E7%9A%84%E5%90%84%E4%B8%AA%E4%BD%8D%E4%B8%8A%E7%9A%84%E6%95%B0%E5%AD%97%E4%B9%8B%E5%92%8C%E7%AD%89%E4%BA%8E160)
x+x+x+y+y=54,x+x+y+y+y=56得出3X+2Y=54,2X+3Y=56扩大后得出6X+4Y=108,6X+9Y=118两式相减得出Y=2得出X=50/3
1/40再问:过程再答:我想让您再发一遍原式行吗?((x+y)的平方-(x-y)的平方-2y(x-1/2y))/4y里的“x-1/2y”是(x-1)/2y还是x-(1/2y)?再问:第二个再答:(x+
原式=(x-y)(x²+2xy+y²-xy)-(x-y)(x²-2xy+y²+xy)=(x-y)(x²+xy+y²)-(x+y)(x&sup
x-y-3绝对值+(2x+2y+10)的平方=0X-Y-3=0X-Y=32X+2Y+10=0X+Y=-5(x+y)(x-Y)=3X(-5)=-15
x²-y²=20﹙x-y﹚﹙x+y﹚=20﹣5﹙x-y﹚=20x-y=﹣4再问:负5是哪里来的?再答:在已知条件中,x+y=﹣5.
|x|+x+y=10|y|+x-y=12两式相加得|x|+|y|+2x=22.(1)两式相减得|x|-|y|+2y=-2.(2)所以-|y|+2y<0若y>0,则显然-y+2y<0,即y<0,矛盾若y
直接解方程好了.x+y=35,3x+y=99则2x=99-35=64,x=32,y=3带进去有2x+3y=73为啥要化简?
x-y=1,x+y=-73(x+y)+20(x-y)-5=3×(-7)+20×1-5=-21+20-5=-6
(x+y)2=25x2+y2+2xy=252xy=25-20=5(x-y)2=x2+y2-2xy=20-5=15x-y=正负根号15如还有不懂的,还可以继续追问哦\(^o^)/~
(x+y)(x+y-10)+25=0设x+y=aa(a-10)+25=0a²-10a+25=0(a-5)²=0a=5∴x+y=5x-y=3x=4y=1
由x^2+y^2-10x-10y=0与x^2+y^2-5x-5y-20=0得两圆的公共弦方程为x+y-4=0,圆x^2+y^2-10x-10y=0的圆心坐标为(5,5),半径为5倍根号2,(5,5)到
x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0x=1y=-3(x-y)/(x+y)=4/(-2)=-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^3+y^3-XY=(x+y)(x^2-xy+y^2)-xy=1×(x^2-xy+y^2)-xy=x^2-xy+y^2-xy=x^2-2xy+y^2=(x-y)^2≥0得证.
(1)x^2+y^2-4x+10y+29=0x^2-4x+4+y^2+10y+25=0(x-2)^2+(y+5)^2=0x=2y=-5剩下的自己解下面两个题目是不是写错了,没看懂
(x+y)(x+y+1)=20(x+y)+(x+y)-20=0(x+y+5)(x+y-4)=0x+y+5=0或x+y-4=0解得x+y-5或x+y=4又因为x+y≥0所以x+y=4.补充的那个题目:令
x²-y²=20平方差公式得(x+y)(x-y)=20x+y=-5∴x-y=20÷(-5)=-4
首先[x,y]=meshgrid(-0.1:0.1,0:0.3);没有取步长可改为[x,y]=meshgrid(-0.1:0.01:0.1,0:0.01:0.3);其次z=0.8-(x+y^2+y-0
x^2+y^2-10x-12y+61=0(x²-10x+25)+(y²-12y+36)=0(x-5)²+(y-6)²=0因为(x-5)²与(y-6)&
若x≤0,|x|=-x|x|+x+y=10y=10代入x+|y|-y=12得x=12>0矛盾,∴x>02x+y=10①若y≥0,x+|y|-y=x=12y=10-2x∴yx-2y=12②联立①②解得x