Answer:
This sum is the sum of an arithmetic sequence. There is a formula for the sum of an arithmetic sequence which can be looked up or derived by a variety of means.
A nice approach for this sequence is the following. Notice that the sum of first and last number in the sequence is the same as the sum of the second and second last, and also the same as the sum of the third and third last, and so on.
There are n of these pairs. So the desired sum is n x (first number + last number). But the first number is 1 and the last on is 2n. Thus the desired sum is n(1 + 2n).
Hope this helps!!
Mark Brainleast!!!!!!!!!!!
Answer:
x = 11, y = 3
Step-by-step explanation:
(13x - 19) and (9x + 25) are corresponding angles and congruent, thus
13x - 19 = 9x + 25 ( subtract 9x from both sides )
4x - 19 = 25 ( add 19 to both sides )
4x = 44 ( divide both sides by 4 )
x = 11
Then
13x - 19 = 13(11) - 19 = 143 - 19 = 124
(17y + 5) and 124 are alternate angles and are supplementary, thus
17y + 5 + 124 = 180, that is
17y + 129 = 180 ( subtract 129 from both sides )
17y = 51 ( divide both sides by 17 )
y = 3