Question 600354
6x+8y+9+2x-y-11


(6x+2x)+(8y-y)+(9-11)


8x+7y-2


So 6x+8y+9+2x-y-11 completely simplifies to 8x+7y-2


In other words, 6x+8y+9+2x-y-11 = 8x+7y-2 for all values of x and y.