Question

calcule o 40° termo da P.A (26,31,36,41...)

Answer 1

a40=?       a40= 26 + (40-1) x 5
n=40          a40= 26+ 39 x5 
a1= 26       a40= 26 + 195
r= 5             a40= 221

Answer 2

$P.A.=(26,31,36,41,...)\to \\\\ a_{n} = a_{1} +(n-1)*r\\\\ a_{n} = a_{40}=?\\ a_{1} = 26\\n=40\\r=5\\ \\a_{40}=26+(40-1)*5\to \\ a_{40}=26+39*5\to\\ a_{40}=26+195\to\\ a_{40}=221$