Answer:

Step-by-step explanation:
We are given with two equations
first equation is 
second equation is

we find the result of subtracting two equation
subtract the second equation from the first, so
first equation - second equation, multiply second equation by -1 and then add it with first equation


Now add both equations, we get

Answer:
the answer is none of those it is 4/13
All three series converge, so the answer is D.
The common ratios for each sequence are (I) -1/9, (II) -1/10, and (III) -1/3.
Consider a geometric sequence with the first term <em>a</em> and common ratio |<em>r</em>| < 1. Then the <em>n</em>-th partial sum (the sum of the first <em>n</em> terms) of the sequence is

Multiply both sides by <em>r</em> :

Subtract the latter sum from the first, which eliminates all but the first and last terms:

Solve for
:

Then as gets arbitrarily large, the term
will converge to 0, leaving us with

So the given series converge to
(I) -243/(1 + 1/9) = -2187/10
(II) -1.1/(1 + 1/10) = -1
(III) 27/(1 + 1/3) = 18
That would be 8 and 9.
9*8=72
While 9+8=17
I hope this helps! (:
????I don’t get what u need help with