Answer:
-25
Step-by-step explanation:
Hope this helps! :)
The sum of the first n odd numbers is n squared! So, the short answer is that the sum of the first 70 odd numbers is 70 squared, i.e. 4900.
Allow me to prove the result: odd numbers come in the form 2n-1, because 2n is always even, and the number immediately before an even number is always odd.
So, if we sum the first N odd numbers, we have

The first sum is the sum of all integers from 1 to N, which is N(N+1)/2. We want twice this sum, so we have

The second sum is simply the sum of N ones:

So, the final result is

which ends the proof.
Answer:
An octagon has eight interior angles.
Interior angle total sum = (n-2) x 180, where n = number of sides.
Since an octagon has 8 sides, we have:
6 x 180 / 8, which is 135.
The answer is 135.
Let me know if this helps!
Answer:
(x + 3)(x + 5)
Step-by-step explanation:
The given expression is x^2 +8x + 15
Now find the factor of 15 such that when you add the factors, we have to get 8
The right factors of 15.
5 * 3 = 15
5 + 3 = 8
The right factors are 3 and 5.
x^2 + 8x + 15 = (x + 3)(x + 5)
Therefore, x^2 + 8x + 15 = (x + 3)(x + 5)
Thank you.
Answer:
O Two times x minus seven plus ten