(reposted for points)
Supplementary angles sum up to 180 degrees.
2x - 4 + 2x + 4 = 180
4x = 180
x = 45
Therefore,
m<9 = 2(45) - 4 = 90 - 4 = 86 degrees
m<10 = 2x + 4 = 90 + 4 = 94 degrees.
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