Question

Piz help me out with this one

Answer 1

hello :
the formula is : an = a1+(n-1)d a1 : the first term d : is the common diff
an = 9+(n-1)(-2)
an =9-2n+2
an = -2n +[ 11 ]

Answer 2

Answer: -2n+9

This is because the starting value is 9, so it has to be included in the equation.