⎩ ⎪ ⎪ ⎨ ⎪ ⎪ ⎧ ​ b(1)=15 b(n)=b(n−1)⋅(−3) ​ What is the 4^{\text{th}}4 th 4, start superscript, start text, t, h, end text, end superscript term in the sequence?