Question

Determine the AP whose 3rd term is 0 and 7th term is 9

Answer 1

Step-by-step explanation:

Given :

a3 = 0,

(a)n = a + (n-1)d

a3 = a + (3-1)d

0 = a + 2d

-2d = a -------(1)

a7 = 9

(a)n = a + (n-1)d

a7 = a + (7-1)d

9 = a + 6d ------- (2)

Substituting (1) in (2) gives ;

9 = -2d + 6d

9 = 4d

9/4 = d

Sub d = 9/4 in (1) gives;

-2(9/4) = a

-9/2 = a

Therefore the AP is :

a, a+d, a+2d, a+3d.....

-9/2, (-9/2)+(9/4), (-9/4)+2(9/4).....

-9/2, -9/4, 9/4......