Answer:
a7 = 27x + 44
Step-by-step explanation:
number of terms (n) = 7
first term (a1) = 3x + 8
second term (a2) = 7x + 14
common difference (d) = a2 - a1 = 7x + 14 - (3x + 8)
= 7x + 14 - 3x - 8
= 4x + 6
= 2(2x + 3)
7th term (a7) = ?
equation :
a7 = a1 + (n - 1) × d
a7 = 3x + 8 + (7 - 1) × 2(2x + 3)
a7 = 3x + 8 + (6) × 2 × (2x + 3)
a7 = 3x + 8 + 12(2x + 3)
a7 = 3x + 8 + 24x + 36
a7 = 27x + 44
