Question

{3x平方-2x(x+y)+y(2x-y)}除以(x+y),其中x=二分之一,y=三分之一先化简再求值？

Answer 1

原式=(3x²-2x²-2xy+2xy-y²)÷(x+y)
=(x²-y²)÷(x+y)
=(x+y)(x-y)÷(x+y)
=x-y
=1/2-1/3
=1/6,5,{3x平方-2x(x+y)+y(2x-y)}除以(x+y),
={3x²-2x²-2xy+2xy-y²}除以(x+y),
=【x²-y²】÷（x＋y）
=x-y
=2分之1-3分之1
=6分之1,0,