B=30. all you have to do is minus 9 from both sides then multiply 6 to each side so all thats left is the variable
Step-by-step explanation:
a1 is the first term. In this case, 2.
r is the common ratio. Each term is multiplied by -3 to get the next term, so r = -3.
an = 2 (-3)ⁿ⁻¹