Question

Determine the 2nd and kth term of an AP whose 9th term is -2.6 and 23rd a
is -5.4
​

Answer 1

Step-by-step explanation:

9th term = a+(n-1)d

=>> a+(9-1)d=-2.6

=>> a+8d=-2.6 ------(1)

23rd term = a+(n-1)d

=>> a+(23-1)d = -5.4

=>> a+22d=-5.4 -----(2)

(2)-(1)

= a+22d=-5.4

a+8d = -2.6

___________

14d =-2.8

=>> d= -0.2

Substituting d=-0.2 in (1)

a+8(-0.2) = -2.6

a-1.6=-2.6

a=-2.6+1.6

a=-1

2nd term = a+(n-1)d = a+(2-1)d

=>> a+d = -1+-0.2 = -1.2

Kth term = a+(n-1)d = a+(k-1)d

=>> -1 + (k-1)-0.2

=>> -1 -0.2k+0.2

=>> -0.8-0.2k

=>> -0.2(4+k)

Hope it will help you...

Answer 2

Step-by-step explanation:

9th term = a+(n-1)d

=>> a+(9-1)d=-2.6

=>> a+8d=-2.6 ------(1)

23rd term = a+(n-1)d

=>> a+(23-1)d = -5.4

=>> a+22d=-5.4 -----(2)

(2)-(1)

= a+22d=-5.4

a+8d = -2.6

___________

14d =-2.8

=>> d= -0.2

Substituting d=-0.2 in (1)

a+8(-0.2) = -2.6

a-1.6=-2.6

a=-2.6+1.6

a=-1

2nd term = a+(n-1)d = a+(2-1)d

=>> a+d = -1+-0.2 = -1.2

Kth term = a+(n-1)d = a+(k-1)d

=>> -1 + (k-1)-0.2

=>> -1 -0.2k+0.2

=>> -0.8-0.2k

=>> -0.2(4+k)