Question

if 18, x, y, -3 are in AP, find x+y​

Answer 1

Answer:

if a,b,c,d are in A.P

then b+c = a+d

x+y = 18+(-3) = 15

Step-by-step explanation:

Answer 2

given, a = 18

a4 = -3 = a + 3d

=> 3d = -3 - 18 = -21

=> d = -7

hence a2 = x = a + d = 18 -.7 = 11

a3 = y = a + 2d = 18 + 2(-7) = 18 - 14 = 4

hence, x + y = 11 + 4 = 15