a. Notice that
1/(1*2) = 1/2 = 1 - 1/2
1/(2*3) = 1/6 = 1/2 - 1/3
1/(3*4) = 1/12 = 1/3 - 1/4
and so on, which suggests the n-th term of the sum can be written as

Then the sum itself is telescoping:



b. The proof is trivial:

so the formula found in (a) is correct.
You are cheating. I see this is a test.
Answer:
i think its 48
Step-by-step explanation:
do 39+9 because the 9 is negative
Answer:
0
Step-by-step explanation:
63 * 0 is 0. 0 * (-7) is also 0.
Anything multiplied by 0 is 0, no matter how big the number is, or how many numbers there are.
Hope this helps :)
Answer:
( 5x-9) (5x+9)
Step-by-step explanation:
25 x^2 - 81
Rewriting
(5x)^2 -9^2
This is the difference of squares
a^2 -b^2 = ( a-b)(a+b)
(5x)^2 -9^2 = ( 5x-9) (5x+9)