Answer:
The commutative property lets you group like terms together:
... 5x +3x +9x +20 +7
Explanation:
If we divide the expression into 4 groups:
...[5x] +(20) +(3x +9x) +[7]
according to the commutative property of addition, we can swap the groups in curved parentheses.
... [5x] +(3x +9x) +(20) +[7]
_____
The distributive property lets you combine x terms:
... (5 +3 +9)x +27
... 17x +27 . . . . . . the simplified form of the expression