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Gelneren [198K]

2 years ago

15

Let $a_1$, $a_2$, . . . , $a_{10}$ be an arithmetic sequence. If $a_1 + a_3 + a_5 + a_7 + a_9 = 17$ and $a_2 + a_4 + a_6 + a_8 +

a_{10} = 15$, what is the value of $a_1$?
GIVING BRAINLIEST>

1 answer:

vfiekz [6]2 years ago

7 0

So

a be first term and d be common difference

a+a+2d+a+4d+a+6d+a+9d=17
5a+21d=17--(1)

And

a+d+a+3d+a+5d+a+7d+a+9d=15
5a+25d=15--(2)

Eq(1)-Eq(2)

-4d=-2
d=1/2

Put in second one

5a+25d=15
a+5d=3
a+5/2=15
a=15-5/2
a=25/2

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