5x+4y=144 (1)

化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y 5x+4y=144 (1) 已知x²+y²+5=2x+4y,求代数式（2x²-（x+y)(x-y))x((x+y-1) 3x-2y=1 4x-5y 1/5x=4y改成比例式x:y():(). 化简求值{(x=2y)(5x-2y)-(3x+2y)(3x-2y)]/4x,其中x=2,y=-1 3x+2y/4=2x+y/5=x-y+1/6 1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [（x+y)(x-y)-(x-y)^2+2y(x-y 微分方程(1)(y'')^2+5y'-y+x=0;(2)y''+5y'+4y^2-8x=0;(3)(3x+2y)dx+( 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y