Question

1.计算1/6x-4y +1/6x+4y — 3x/4y^2-9x^2

Answer 1

[1/2(3x-2y)]+[1/2(3x+2y)]+[3x/(3x+2y)(3x-2y)] =[(3x+2y)/2(3x+2y)(3x-2y)]+[(3x-2y)/2(3x+2y)(3x-2y)] +[6x/2(3x+2y)(3x-2y)] =[6x/2(3x+2y)(3x-2y)]+[6x/2(3x+2y)(3x-2y)] =[6x/(3x+2y)(3x-2y)]