Question

three numbers are in ap.product of first and third is 5times of common difference.find ap​

Answer 1

a-d, a,a+d

(a-d) (a+d)=5d

a^2-d^2=5d

a^2= 5d+d^2

a^2= d(d+5)

now if you see clearly the number which are differences by 5 then we multiply with we should get a perfect square number

so that means that number 4

so that means d=4

a^2=36

a=6

so that ap is

2,6,10