Question

10 pts


Find a , b such that 18, a, b, -3 are in AP.​

Answer 1

common difference = a - 18 = -3 - b

. a + b = 15

. b = 15 - a

Also, d = a - 18 = b - a

. a + a - b = 18

. 2a - 15 + a = 18

. 3a = 18 + 15

. a = 33÷3

. a = 11

Putting this value in common difference,

. 11 - 18 = -3 - b

. b = 4

Hence, a = 11, b = 4

Answer 2

Answer:

common difference = a - 18 = -3 - b

. a + b = 15

. b = 15 - a

Also, d = a - 18 = b - a

. a + a - b = 18

. 2a - 15 + a = 18

. 3a = 18 + 15

. a = 33÷3

. a = 11

Putting this value in common difference,

. 11 - 18 = -3 - b

. b = 4

Hence, a = 11, b = 4