The first step in simplifying this expression is to identify which, if any, terms can be combined. Remember, only like terms — constant terms or terms with the same variable — can be combined.
( -3x+ 7)+( -6x+ 9)
In this case, we have two x-terms and two constants. Let's arrange the like terms in columns. Then, let's perform the addition.
-3 x + 7 &
(+) -6 x + 9&
-9 x + 16&
Therefore, we get the following result.
(-3x+7)+(-6x+9) = -9x + 16
