$n^{ ext {th }}$ term of an A.P. is $7 n+4$. The common difference is:\

Question

$n^{	ext {th }}$ term of an A.P. is $7 n+4$. The common difference is:\

Professor PC Thomas Classes · Answer

(c): We have, $a_{n}=7 n+4$\ $	herefore a_{1}=7 	imes 1+4=7+4=11$\ and $a_{2}=7 	imes 2+4=14+4=18$\ So, common difference $=18-11=7$ \ Commonly made mistake - Don't misunderstand the difference between a term and its position in the sequence, clearly identify the position ( $n$ ) and the term ( $a_{n}$ ) before applying formula.