X2 + 2x = 2x + x2
associative property
closure property
commutative property

Commutative Property

x² + 2x = 2x + x²

is of the general form

a + b = b + a

The order of the terms in an addition doesn't matter.  That's called the commutative property of addition.

the answer would be 1 1/72

step-by-step explanation:

you can rewrite the equation by separating the parts and then solving individually:

10-9=1

1/8 - 1/9=

find l c d and then combine:

1 1/72