Answer:
-2x + 3
Step-by-step explanation:
Perimeter means to add all the sides of the triangle. Simply combine like terms:
(3x) + (2x - 5) + (-7x + 8)
(3x + 2x - 7x) + (-5 + 8)
(5x - 7x) + (8 - 5)
-2x + 3 is your answer.
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