已知x=y加4,求代数式x的平方-2xy加y的平方-25的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/18 09:28:06
(Y+1)^-(Y^-4X)=y*y+2y+1-y*y+4x=2y+4x+1=2(y+2x)+1把y+2x=1代入,得:2*1+1=3所以原代数式的值为3.
实数x,y满足x-4的绝对值+根号y+11=0所以有:X-4=0且Y+11=0得X=4,Y=-11所以,X-Y=4-(-11)=15.
x^2+y^2+2x+4y=-5(题目错了吧?)x^2+2x+1+y^2+4y+4-5=-5(x+1)^2+(y+2)^2=0x=-1,y=-2,所以:x/y+y/x=1/2+2=2.5
X-5=0,X=5,Y+4=0.Y=-4,X+Y=1,1的2006次=1
2x-y分之x+y=2,则2x-y=2(x+y)4x-2y分之x+y-4x+4y分之2x-y=2(2x-y)分之x+y-4(x+y)分之2x-y=4(x+y)分之x+y-4(x+y)分之2(x+y)=
7-x+y-(y-x)=7-(x-y)+(x-y)……(这步添括号,y-x=-(x-y),代入x-y=3)=7-3+3=77^2=49(7的平方等于49)
(2x-y)/(x+y)=2两边同时乘以22*(2x-y)/(x+y)=2*2把2乘以进去,有(4x-2y)/(x+y)=4(2x-y)/(x+y)=2两边取倒数,有(x+y)/(2x-y)=1/2两
x+y分之4x-2y-2x-y分之4x+4y=2(2x-y)/(x+y)-4(x+y)/(2x-y)=2*2-4*(1/2)=4-2=2
即(x+y)²=0x+y=0原式=x²+4xy-x²+4y²=4y(x+y)=0再问:=4y(x+y)看不懂再答:4xy+4y²=4y(x+y)
已知y/x=2,则求代数式x+y/4x-5y的值分子分母同除以xy;=(1+y/x)/(4-5y/x)=(1+2)/(4-5×2)=3/(-6)=-1/2;您好,很高兴为您解答,skyhunter00
=3-2(x+2y)=3-2x3=3-6=-3
答案是2.4x-2y/x+3y=(2x-y/x+3y)乘以2=4,4x+12y/2x-y=(x+3y/2x-y)乘以4=1/2x4=2,所以代数式等于4-2=2.
当x=4,y=6时x+y的绝对值是10当x=-4,y=6时x+y的绝对值是2当x=-4,y=-6时x+y的绝对值是10当x=4,y=-6时x+y的绝对值是2
7-x+y-(y-x)^2=7-(x-y)-(x-y)^2把x-y=3代入原式=7-3-3^2=-5
已知(2x-y)/(x+y)=2,则(4x-2y)/(x+y)=4,(x+y)/(2x-y)=1/2,(4x+4y)/(2x-y)=2(4x-2y)/(x+y)-(4x+4y)/(2x-y)=4-2=
7-x+y-(y-x)^2=7-(x-y)-(x-y)^2=7-3-3^2=4-9=-5
解法一:由x+y=−4x−y=8得x=2y=−6,(4分)所以x2-y2=22-(-6)2,(6分)=-32.(8分)解法二:x2-y2=(x+y)(x-y),(4分)=-4×8,(6分)=-32.(
原式化简=x+2y=2011
解题思路:运用完全平方公式和平方差公式进行化简,再代入数值进行计算解题过程:解: