7x7x7×7国产成人yy

聂荣使3397X的5/7等于y的1/6,那么x:y等于多少? -
骆翠斌19415508461 ______ X的5/7等于y的1/6,那么x:y等于7:30;5/7x=1/6y x:y=1/6:5/7=7:30

聂荣使3397(x - y)的三次方*(y - x)七次方*(x - y)的四次方 -
骆翠斌19415508461 ______ (x-y)^3*(y-x)^7*(x-y)^4 =(x-y)^(3+4)*(y-x)^7 =(x-y)^7*(y-x)^7 =[(x-y)(y-x)]^7 =[-(x-y)^2]^7 =-(x-y)^14

聂荣使3397甲堆煤的五分之三等于乙堆煤的七分之三,那么甲堆煤与乙堆煤的比是< > -
骆翠斌19415508461 ______ 3/5÷3/4=1.25 甲堆煤的质量是乙堆的1.25倍

聂荣使3397x*y= - |y|,x△y= - x,如x=3,y=4时,x*y= - |4|= - 4x△y= - 3那么比较,5*( - 7)与5△( - 7) -
骆翠斌19415508461 ______ 5*(-7)∵xy=-|y|,xΔy=-x ∴x=5,y=-7 ∴x*y=-|y|=5*(-7)=-|-7|=-7,xΔy=-x=5Δ(-7)=-5 ∴5*(-7)

聂荣使3397直线Y=X+1关于直线Y=2X的对称直线的方程是什么 -
骆翠斌19415508461 ______ 联立方程得交点为(1,2),设对称直线方程为y-2=k(x-1) 由夹角公式(k-2)/(1+2k)=(2-1)/(1+2*1)=1/3解得k=7 y-2=7x-7即7x-y-5=0为所求.

聂荣使339738+8(4 - X)=7X+2 -
骆翠斌19415508461 ______ 38+8(4-X)=7X+238+32-8x=7x+2-8x-7x=2-38-32-15x=-68 x=68/15

聂荣使33973x+2y/4=2x+y/5=x - y+1/6 -
骆翠斌19415508461 ______ (3x+2y)/4=(2x+y)/55*(3x+2y)=4*(2x+y)15x+10y=8x+4y7x= -6y x= -6/7y(2x+y)/5=(x-y+1)/66*(2x+y)=5*(x-y+1)12x+6y=5x-5y+57x= -11y+5 把x= -6/7y 带入上式:7*( -6/7y )=-11y+5-6y=-11y+55y=5 y=1 因为x= -6/7y y=1 所以x= -6/7y

聂荣使339716(x+y)2 - 9(x+y)2
骆翠斌19415508461 ______ 16(x+y)2-9(x+y)2=(x+y)2(16-9)=7(x+y)2

聂荣使3397已知X+Y=7,XY=2,求①2X²+2Y²的值;②(X - Y)²,的值 -
骆翠斌19415508461 ______ 2X²+2Y²=90; (X-Y)²=41

聂荣使3397x - y=5x+y=7x^2 - y^2等于多少 -
骆翠斌19415508461 ______ x-y=5 x+y=7 相加:2x=12 x=6 y=x-5=1 x^2-y^2=36-1=35 或x^2-y^2=(x+y)(x-y)=5*7=35