方程0.6x+x=96（）

A.x＝12

B.x＝16

C.x＝18

D.x＝16/3

A.x=2

B.x=4

C.x=8

D.x=16

分别求母线平行于x轴及y轴而且通过曲线2x^2+y^2+z^2=16和x^2+z^-y^2=0的柱面方程．

A.椭圆柱面3x²+2z²=16；

B.椭圆柱面x²+2y²=16；

C.双曲柱面3y²-z²=16；

D.抛物柱面3y²-z=16．

A.15

B.16

C.29

D.30

A.X²/10－Y²/8=1

B.Ⅹ²/25－Y²/16=1

C.X²/16－Y²/25=1

D.X²/100－Y²/64=1

A.①

B.②

C.③

D.④

A.2x-4-12x＋3＝9，-10x＝9＋4-3＝10，x＝1

B.2x-4-12x＋3＝9，-10x＝10，x＝-1

C.2x-4-12x－3＝9，-10x＝16，x＝-8/5

D.2x-2-12x－3＝9，-10x＝2，x＝-1/5

为x处,任意时刻t的水击压强表示式ξ ₁₁.

nction is depicted by the formula C = 5X + 6Y, where C = contribution, X = the number of product X to be produced and Y = the number of product Y to be produced. Each unit of X uses 2 kg of material Z and each unit of Y uses 3 kg of material Z. The standard cost of material Z is $2 per kg. The shadow price for material Z has been worked out and found to be $2·80 per kg. If an extra 20 kg of material Z becomes available at $2 per kg, what will the maximum increase in contribution be？

A.Increase of $96

B.Increase of $56

C.Increase of $16

D.No change

A.(62)16

B.(96)16

C.(61)16

D.(60)16