d = 7
The sum to n terms of an arithmetic sequence is
S[tex]_{n}[/tex] = n/2[ 2a₁ + (n - 1 )d]
here S₉ = 297
thus 9/2[ (2 × 5) + 8d] = 297
multiply both sides by 2 and divide by 9
10 + 8d = 66
subtract 10 from both sides
8d = 66 - 10 = 56
divide both sides by 8
d = [tex]\frac{56}{8}[/tex] = 7
