how to solve the equation

manisha

New member
Joined
Oct 24, 2012
Messages
11
hello there

I want to know each and every step in detail to solve this equation.


n/2[2a + (n - 1)d] = 1800
please reply quickly

thanks,
 
hello there

I want to know each and every step in detail to solve this equation.


n
/2[2a + (n - 1)d] = 1800
please reply quickly

thanks,

Solve for what? n, a or d?

Please read the post titled "Read before Posting".

We can help - we only help after you have shown your work - or ask a specific question (not a statement like "Don't know any of these")

Please share your work with us indicating exactly where you are stuck - so that we may know where to begin to help you.
 
ok then,

actually i was solving
The sum of how may tersm of the series 6 + 12 + 18 + 24 + ... is 1800 ? this question which is an example of arthmetic progression

where
a = 6, d = 6 and Sn = 1800 then i came across this equation which i dident understand how to solve
Then, n[2a + (n - 1)d] = 1800
2
so please explain me in detail....
thanks and regards
 
ok then,

actually i was solving
The sum of how may tersm of the series 6 + 12 + 18 + 24 + ... is 1800 ? this question which is an example of arthmetic progression

where
a = 6, d = 6 and Sn = 1800 then i came across this equation which i dident understand how to solve
Then,
n
[2a + (n - 1)d] = 1800
2
so please explain me in detail....
thanks and regards
I am presuming that what is in the box above is:

\(\displaystyle \{n[2a + (n - 1)d]\}/2 = 1800?\) It helps to use grouping symbols and / for division

If I substitute in a = 6 = d and Sn = 1800

\(\displaystyle 1800 = \dfrac{n\{2*6 + 6(n-1)\}}{2} = \dfrac{6n(2 + n - 1)}{2} = 3n(n + 1) \implies n(n + 1) = 600.\)

What is so hard about that? Of course, that is going all around Robin Hood's barn.

\(\displaystyle 6 + 12 + 18 +\ ...\ = 1800 \implies\)

\(\displaystyle 6(1 + 2 + 3 +\ ...) = 6(300) \implies\)

\(\displaystyle 1 + 2 + 3 +\ ...\ = 300 \implies \dfrac{n(n + 1)}{2} = 300 \implies n(n + 1) = 600?\)

Or are you having trouble solving \(\displaystyle n^2 + n - 600 = 0?\)
 
how to solve this equation

thanks for ur reply


yes ,
firstly i was not unable to understand how 3n(n+1)=1800 was found , but naw i got this (6 is common right )
and again naw how to solve this equation
n2 + n - 600 = 0


thank and regards,
 
I am presuming that what is in the box above is:

\(\displaystyle \{n[2a + (n - 1)d]\}/2 = 1800?\) It helps to use grouping symbols and / for division

If I substitute in a = 6 = d and Sn = 1800

\(\displaystyle 1800 = \dfrac{n\{2*6 + 6(n-1)\}}{2} \implies\)

\(\displaystyle 1800 = \dfrac{6n(2 + n - 1)}{2} \implies\)

\(\displaystyle 1800 = 3n(n + 1) \implies \)

\(\displaystyle n(n + 1) = 600.\)



\(\displaystyle 6 + 12 + 18 +\ ...\ = 1800 \implies\)

\(\displaystyle 6(1 + 2 + 3 +\ ...) = 6(300) \implies\)

\(\displaystyle 1 + 2 + 3 +\ ...\ = 300 \implies \)

\(\displaystyle \dfrac{n(n + 1)}{2} = 300 \implies \)

\(\displaystyle n(n + 1) = 600\)

It's from an equation to an equation using implications.
 
Top