作业帮20x 15y 25(y-0.6)=145怎么解
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/27 09:15:19
4(x+y)^2-20(x+y-1)+5=4(x+y)^2-20(x+y)+20+5=4(x+y)^2-20(x+y)+25=[2(x+y)]^2-2*[2(x+y)]*5+5^2=[2(x+y)-5
x+y=20-6=14x+y=14x=14-y3(14-y)+y=3042-3y+y=3042-2y=302y=12y=6x=8
原式=(x-y)(x²+2xy+y²-xy)-(x-y)(x²-2xy+y²+xy)=(x-y)(x²+xy+y²)-(x+y)(x&sup
由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y
5y（x-2y）²-20y（2x-y）²=5y[(x-2y)²-4(2x-y)²]=5y[(x-2y)+2(2x-y)][(x-2y)-2(2x-y)]=5y(
4(x+y)^2+25-20(x+y)=(2x+2y-5)^2再问：过程
20(x+y)+25+4(x+y)^2=4(x+y)^2+25+20(x+y)=(2x+2y+5)^2你的好评是我前进的动力.我在沙漠中喝着可口可乐,唱着卡拉ok,骑着狮子赶着蚂蚁,手中拿着键盘为你答
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{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由（1）*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36
1)4x-3(20-x)=6x-7(9-x)4x-60+3x=6x-63+7x(4+3-6-7)x=-63x=1/22)4(2y+3)=8(1-y)-5(y-2)8y+12=8-8y-5y+1021y
y=6,x=44
20%y除以5=0.620%y=320y=300y=15
4（x+y)^2+25-20(x+y)=[2(x+y)]²-2×2(x+y)×5+5²=[2(x+y)-5]²=(2x+2y-5)²
(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90)=x-2x-3x-4x-..-10x+y*(1-1/2-1/6-1/12-..1/90
第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗
4(x+y)-20(x+y)+25=[2(x+y)]²-2×2×5(x+y)+5²=[2(x+y)-5]²
3（X+Y）+2(X-Y)=20可以化简为5X+Y=20.1式0.3X+0.6Y=60可以化简为X+2Y=200.2式联立1式和2式消元即可以求解这组二元一次方程组X=-160/9Y=980/9
-5x³y(x-y)³+20y[x²(y-x)]²=-5x³y(x-y)³+20yx⁴(x-y)²=-5x³
(3x+2y)/(6x-5y)