Question

If for an A. P d = -4 then t20 - t15 is what?​

Answer 1

Step-by-step explanation:

$- 20 \: is \: your \: answer$

Supposition of Terms in an A.P.

(1) Three terms as : a -d, a,a + d .

(2) Four terms as : a -3d , a - d , a + d , a + 3d .

(3)Five terms as : a -2d , a - d , a , a+ d, a + 2d.

To know the solution with Proof

Refer To the above attachment .

Hope this helps you !!

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Answer 2

Answer:

As P. d=-4

Step-by-step explanation:

so multiplying both side of equation by - 1

=> - P.d=4. and since 20 =5×4 so 20=5(-P.d) ==> - 5t(P.d)

=> and as -t15=-t20+t5 so it is +5t(P.d)+t5

so - 5t(P.d) +5t(P.d) +t5

answer is t5