Question

find 4 terms of AP such that their sum is -8 and product is 385

Answer 1

Let four terms in A.P be (x+3y),(x+y),(x-3y) and (x-y)
sum is -8
therefore

$(x + 3y) + (x + y) + (x - 3y) + (x - y) = - 8 \\ 4x = - 8 \\ x = - 2$


product is 385
therefore

$(x - 3y) \times (x - y) \times (x + 3y) \times (x + y) = 385$
put the value of x=-2
$(2 - 3y)(2 - y)(2 + 3y)(2 + y) = 385$
now solve the equation and get the value of y