# Question #14967

$- 2 a + 7 = 7 - 2 a$
Addition has a property known as commutativity, meaning that for any $x$ and $y$, we have $x + y = y + x$.
In this case, if we let $x = - 2 a$ and $y = 7$, that property directly shows that the two given expressions are equal:
$\left(- 2 a\right) + 7 = 7 + \left(- 2 a\right) = 7 - 2 a$