Math, asked by ajayay9447, 6 months ago

Sum of first 10 terms of an arithmetic sequence is 350 Sum of first 15 terms is 750
Find 8th term of the sequence.

Answers

Answered by Anonymous
9

Given:-

sum of 10 term =350

a+9d=350 ----(i)

sum of 15 term=750

a+14d=750-------(ii)

so, subtracting (i) from(ii) ,we get..

 \frac{a + 14d = 750}{a + 9d = 350}  \\  \\ 0 + 5d = 400 \\  \\ 5d = 400 \\ d =  \frac{400}{5} \\ d = 80

d=80------(iii)

putting the value of eq.iii in eq. i

a+9d=350

a+9*80=350------(in place of d we put the value of a+720=350.

which is given in the equation

. iii)

a=350-720

a= -370.

so now we find the value of 'a' and 'd'

now by using these values we can find 8th term.

 a8= a + (8 - 1)d \\  a8= a  + 7d \\  a8=  - 370 + 7 \times 80 \\  a8=  - 370 + 560  \\ a8 = 190

so your answer will be

8th term 190..............✔️✔️✔️✔️

#hope it will help you#

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