maxz=7x+12y 9x+4y≤360 4x+5y≤200 3x+10y≤300 x≥0,y≥0 如何解,需要用到什么公式?maxz应该=42.8

maxz=7x+12y 9x+4y≤360 4x+5y≤200 3x+10y≤300 x≥0,y≥0 如何解,需要用到什么公式?maxz应该=42.8 线性规划问题 maxz=4x-5y 这是一个目标函数,在坐标轴里怎么画,应该要设x=多少 4+12(x-y)+9(x-y)^ 7x:4y,x:y=( ):( 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 21/(x+y)+4/(x-y)=12/(x+y)+7/(x-y)结果为(x+y)/(x-y)=3求过程! 4-12(x-y)+9(x-y)²=? 9(x-y)^2-12(x-y)+4=快 4-12(x-y)+9(x-y)的平方= 因式分解：4+12(x+y)+9(x-y)^2=? 因式分解(x+y)^2y^2-12(x+y)y^2+36y^2-y^4 5X+16X= Y+9Y= X+7X-4X= 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x+y)²-12(x+y)(x-y)+9(x-y)² 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 方程题4道1.4(x-y-1)=3(1-y)+3.5 (x/2)+(y/3)=2 2.2(x-y)/3-(x+y)/4=13/6 6(x+y)-4(2x-y)=16 3.3x-y+z=3 2x+y-3z=9 x+y+z=12 4.5x-4y+4z=13 2x+7y-3z=19 3x+2y-z=18 4x³y+12x²y²+9x y³/4x³-9x y²,其中x=1,y=1.