Question

Find the $\text{2}{\text{7}}^{\text{th}}$ term of the AP 9, 4, -1, -6, -11....

Answer 1

Given $AP\to 9,4,-1,-6,-\mathrm{11.....}$

Common difference $=4-9=-5$

${27}^{th}$ term $a_{27}=a+(27-1)d$

$=9+26\times (-5)$

$=9-130$

$=-121$