s=3x^2+2y^2 18+8y+40求s最小值本人是初中生

s=3x^2+2y^2 18+8y+40求s最小值本人是初中生 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 12y(x-y)^2-8(x-y)^3=? 已知全集S={(x,y)|x^2+y^2 |x|+|y|=3,s=2|x|+|y|,求s的最大值和最小值 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 18(x+y)^8(x-y)^7÷[3(x+y)^3(x-y)^3]^2 x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 因为x=y,所以2x=2y,所以2s-(x+y)=2y-(x+y),即x-y=y-x则(x-y)/(y-x)/(x-y)对不对 求几个方程组的答案 ｛2x+y=2 {3x-y=7 x=?y=?{x+2y=50 {3x=2y+6 x=?y=?{x+y=40 {10x+8y=370 x、y=?{x+y=5.8 {y=3x+0.6 x=?y=? S=(x+1/y)+(x^2+1/y^2)+.+(x^n+1/y^n) 请问S=max{2x+y , 设S＝｛y|y=3^x,∈R},T={y|y=x^2-1,x∈R}.求S∩T (x+y)(x+2y)(x+3y)(x+4y)=-40y的值为根号11 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一