Write a recursive formula for 3, 20, 37, 54

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

A3cm×3cm\greend{3\,\text{cm} \times 3\,\text{cm}} 3cm×3cm start color greend, 3, space, c, m, times, 3, space, c, m, end color greend rectangle sits inside a circle with radius of 4cm\blued{4\,\text{cm}} 4cm start color blued, 4, space, c, m, end color blued . what is the area of the shaded region? round your final answer to the nearest hundredth.

Asap easy 6th grade 30 pts describe how to rewrite a power with a positive exponent so that the exponent is in the denominator.