Step-by-step explanation:
given,
MP = x - 8
PN = 3x - 9
MN = 21
we know,
according to segment addition postulate AB + BC = AC
now,
MP + PN = MN
→ x - 8 + 3x - 9 = 21
→ 4x - 17 = 21
→ 4x = 21 + 17
→ 4x = 38
→ x = 38/4 = 9
→ x = 9
therefore, value of x is 9.
hope this answer helps you dear! take care
