Write an expression for the eighth partial sum of the series using summation notation

option B

Step-by-step explanation:

9/10 + 6/5 + 3/2...........

We find the difference between the terms

We will get the same difference when we subtract consecutive terms.

so , d= 3/10, a= 9/10

we find the formula for nth term

a_n = a+(n-1) d

we need to find eighth partial sum so we  take n=1 to 8

sum of 8 terms ()

So option B is correct

angles 1 and 3 are vertical angles, meaning that they are equal to each other. to solve this you may set angle 1 and 3 equal to each other and just solve for x like

110 = 2x + 10

100 = 2x

50 = x

check:

110 = 2* 50 + 10

110 = 100 + 10

110 = 110

hope this !

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