Please help with this math problem! Will give brainliest! :)
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Answer:
9
Step-by-step explanation:
All triangles (3 sided polygons) have angles added up to 180, so we can do the following:
(7x-1) + (7x+8) + (5x+2) = 180° - equation
7x-1 + 7x+8 + 5x+2 = 180° - "distribute"
19x - 1 + 8 + 2 = 180° - combine the x terms
19x + 9 = 180° - combine the integer terms
19x = 171 - subtract 9 form both sides
x = 9 - divide both sides by 19