求证3x^2-8xy+9y^2-4x+6y+13＞0

求证3x^2-8xy+9y^2-4x+6y+13＞0 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 因式分解30题(要过程)am+an+bm+bn x^2+5y-xy-5x x2+xy+2xz+x (a+b)x-(b+a)y -12x(x-y)-(y-x)x^2 2x^2+4x+2 x(x+z)-y(y+z) 2(x^2-3ab)+x(4a-3b) 4x^2+12xy+9y^2-25 x^4-16 16x^4-1 x^2+9x+8 x^2-10xy+24y^2 2x^2+15xy-8y^2 3x^2-6xy+3y^2 24x^2+22x-21 -x^2+4xy- 已知xy>0且x≠y,求证：log(x^4+6x^2y^2+y^4)>log(4xy(x^2+y^2)) 已知4x²+4xy+y²-4x-2y+1=0,求证2x²+3xy+y²-x-y=0 已知x,y都是正整数,求证x^3+y^3>=x^2y+xy^2 xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 因式分解：3x^2y+6xy-4x-8 因式分解 3x^2-6xy-4x+8y 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 已知实数x,y,z满足x=6-y,z^2=xy-9,求证：x=y 3(x-y)²-7(x-y)+8(x-y)²+6(x-y)求详细过程（2） 5xy-4x²y-8xy²+3xy-xy²+4x²y x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值