How to find the value of a when the arithmetic mean of a+7 and a+3 is 3a+9? tama po ba ung given? yan ksi ung nkalagay sa libro eh, pero nung triny kong sinlove at chineck, prang mli ung nkuha ko eh pero ok nmn mga solutions ko, wla nmng mli pero prang ksing ung given ang mali? check nyo lng po thank you

1
You have to solve for the arithmetic mean.

Answers

The Brainliest Answer!
  • Brainly User
2016-07-09T11:49:16+08:00
Since 3a + 9 is the arithmetic mean, the arithmetic sequence is:

a+7,  3a+9,  a+3

To solve for a to prove that 3a + 9 is the arithmetic mean:

  (a+7) + (a+3) 
-------------------- = 3a + 9
           2

a+7 + a+3 = (3a+9) (2)

2a + 10 = 6a + 18

6a - 2a = 10 - 18

4a = -8

4a/4 = -8/4

a = -2

ANSWER:  s = -2

Check:

a + 7 = (-2) + 7 = 5

3a + 9 = 3(-2) + 9  ⇒ (-6) + 9 = 3

a + 3 = (-2) + 3 = 1

The arithmetic sequence is: 5, 3, 1
The common difference is 2.
1 5 1
wow!! astig!! paano nyo po nakuha ung equation??
It's in your textbook, and from someone who teaches Math, it comes out naturally. Actually, you can also do this solution. Arithmetic Means between two terms = (a + b) / 2. This solution also entails knowledge in solving linear equation :-) Have a great weekend, and enjoy learning. By the way, there are also students here who are good in Math. Just use your discretion which answer you'll choose by checking the profile of the user who post their answers :-)