Algebra-1

To find the explicit formula for the sequence 3,7,11,15,…, identify the common difference and use the formula for an arithmetic sequence:

Determine the common difference d:

The sequence increases by 4 each time (e.g., 7−3=4, 11−7=4).

Use the formula for the n-th term of an arithmetic sequence:

= + (n − 1)d

Where  = 3 and d=4.

Substitute these values into the formula: