Question

{a1+a8=41 {a17-a5=60
a1,r=?
(Progresii aritmetice)

Answer 1

a1+a-8=41 => a1+a1+7p=41

2a1+7p=41

a17-a5=60 => a1+16p-a1-4p=60

12p=60

p =60:12

p=5

2a1=41-7p

2a1=41-35

2a1=6

a1=6:2

a1=3