Question

X - 1 ,X, X + 1 , X + 2 are in an arithmetic sequence
o- if the product of first and third terms of the sequence is 15 what is its first term ​

Answer 1

Step-by-step explanation:

given that  (x-1)(x+1)=15

                $x^{2} -1^{2}$ = 15

                     $x^{2}$   = 15 +1

                      x = $\sqrt{15+1}$

                      x = $\sqrt{16}$

                       x = 4