Question

If 3, x, y, -9 are in A.P, find the values of x and y.​

Answer 1

• x = -1
• y = -5

Explanation:

The common difference (d) can be found using the first and 4th terms:

a1 = 3

a4 = a1 +d(4 -1)

-9 = 3 +3d . . . . . simplify

-3 = 1 + d . . . . . . divide by 3

-4 = d . . . . . . . . . subtract 1

Then ...

x = a1 + d = 3 -4 = -1

y = x + d = -1 -4 = -5

The values of x and y are -1 and -5, respectively.