Question

a3+a19=10 calculati a6+a16

Answer 1

Orice termen al unei progresii aritmetice poate fi scris ca
$a_{n}=a0+n*r$
In cazul tau avem
$a_{3}+a_{19}=a_{0}+3r+a_{0}+19r=2a_{0}+22r=10$
In a doua suma avem
$a_{6}+a_{16}=a_{0}+6r+a_{0}+16r=2a_{0}+22r=10$