Question

the 3rd term of an arithmetic sequence is 25 and it's 5ty term is 15 what is the first term​

Answer 1

Step-by-step explanation:

first term= a

a+(3-1)d= 25

a+2d=25 - eq(1)

a+4d=15 - eq(2)

(1)-(2)

-2d= 10

d= -5

a+2(-5)=25

a-10=25

a= 35