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Explanation:
"Bisect" means to cut in half
M is the midpoint as it cuts segment ST in half
SM and MT are the same length
SM = MT
2x+3 = 4x-7
2x-4x = -7-3
-2x = -10
x = -10/(-2)
x = 5
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If x = 5, then
SM = 2x+3 = 2(5)+3 = 10+3 = 13
MT = 4x-7 = 4(5)-7 = 20-7 = 13
Both SM and MT are the same length (13 units). This confirms the answer.