新gre数学重要考点：Commutative Law
Commutative Law
Like real numbers, the order does not affect the product or sum of algebraic terms.
Example:
sum:3x+5y=5x+3y,2x2+4y+1=4y+1+2x2,(3x+2)+(y-4)=(y-4)+(3x+2).
product:3x*5y=5y*3x,2x2*4y=4y*2x2,x2yz=yx2z=xzyx,(3x+2)*(y-4)=(y-4)*(3x+2)
Remember:
Subtraction is not commutative:(x+y)-(2x-y) ≠(2x-y)-(x+y)
Division is not commutative:(x+y)/(2x-y) ≠(2x-y)/(x+y)
