Respuesta :

Answer:

54

Step-by-step explanation:

Given

  • a₁₈ = 42
  • a₂₅ = 56

Solving

  • a₁₈ = a + 17d = 42 (1)
  • a₂₅ = a + 24d = 56 (2)
  • (2) - (1)
  • a + 24d - a - 17d = 56 - 42
  • 7d = 14
  • d = 2
  • a = 56 - 24(2) = 56 - 48
  • a = 8

Finding a₂₄

  • a₂₄ = a + 23d
  • 8 + 23(2)
  • 8 + 46
  • 54