math

Thread Starter

mozikluv

Joined Jan 22, 2004
1,437
hello everybody,

how about refreshing the mind of an old cow on how to solve this algebraic equation? solve for x

(12-x/5) - (x/5) = 0.835

pls. show the step by step procedure

mucha mucha gracias
:D :D :D
 

Firestorm

Joined Jan 24, 2005
353
Originally posted by mozikluv@Apr 13 2005, 09:30 PM
hello everybody,

how about refreshing the mind of an old cow on how to solve this algebraic equation? solve for x

(12-x/5) - (x/5) = 0.835

pls. show the step by step procedure

mucha mucha gracias
:D :D :D
[post=6909]Quoted post[/post]​
welp here goes lol :)
(12-x/5) - (x/5)=0.835
first you have to get x by itself on one side or the other.
You probly know the saying Please excuse my dear aunt sally (order of operations)
not really sure on your (12-x/5): Is just x over 5 or is everything(12-x)/5?
I am going to work this out assuming it is all over 5
first move (x/5) over to the right side of the = mark by adding it to both sides.
heres your eqn. now:
(12-x/5)=0.835+(x/5)

Now get rid of the fraction (5) on the left side by multiplying it to both sides
5(12-x/5)=5(0.835)+5(x/5)--->just showing the setup
(12-x)=4.175 + x
no need for parenthesis anymore now :)
12-x=4.175+x
add x to the right side
12=4.175+2x
subtract 4.175 from both sides
7.825=2x
divide by 2
3.9125
:)
If it is the other way around I will work it out 2 if you need me 2
does this recall old math classes? lol ;)
btw-still working understanding the transistor array moz, will try to update it shortly :D
thx l8er

-fire
 

Thread Starter

mozikluv

Joined Jan 22, 2004
1,437
hi,

now why didn't i think of that "to get x by itself on one side or the other" maybe am getting too much cholesterol in my brain
:D :D :D

thanx mucho mucho B) firestorm
 

pebe

Joined Oct 11, 2004
626
Originally posted by Firestorm@Apr 14 2005, 04:18 AM
........not really sure on your (12-x/5): Is just x over 5 or is everything(12-x)/5?
I am going to work this out assuming it is all over 5........

-fire
[post=6919]Quoted post[/post]​
No, multiplication or division is always done first, before adding or subtracting, unless the + or – term is enclosed within brackets. So the first part of the equation is 12 minus one-fifth of x.

Now subtracting the second term (again one fifth of x) gives 12 minus two fifths of x, for left hand side of the equation. Now multiply by -1 to change all the signs, to -12 +2/5 = -0.835

Take the -12 across and change the sign, then 2x/5 = -0.835 + 12 (= 11.165)
Cross multiplying the 5 simplifies to 2x = 11.165 * 5 (= 55.825)

So x = 27.9125
 

Firestorm

Joined Jan 24, 2005
353
yes, thats if the answer for the 1st way :)
The only reason it might be the other way is if he forgot to put the () aound it all since the fraction is at an angle. It shows the method though ;)
thx l8er

-fire
 

Thread Starter

mozikluv

Joined Jan 22, 2004
1,437
hi,

thanx pebe for additional input for the problem that i have presented. actually i had the answer or the value of "X" which is 3.91 rounded off. it's just i don't know how the answer was arrive at. Firestorm solved it and he got the same answer, likewise a newly graduate engineering student passed by the house and i also ask him to solve it for me and he also got the same answer.

:D moz
 

pebe

Joined Oct 11, 2004
626
Originally posted by mozikluv@Apr 16 2005, 03:25 AM
hi,

thanx pebe for additional input for the problem that i have presented. actually i had the answer or the value of "X" which is 3.91 rounded off. it's just i don't know how the answer was arrive at. Firestorm solved it and he got the same answer, likewise a newly graduate engineering student passed by the house and i also ask him to solve it for me and he also got the same answer.

:D moz
[post=6980]Quoted post[/post]​
Hi Moz. If you got the answer 3.91 then it was not the answer to the equation you had shown.

The '/' symbol, in the context of a formula or equation, means 'divided by' and the usual mathmatical rules apply.
 

Firestorm

Joined Jan 24, 2005
353
yea, you have to be careful how you write eqn's. To get 3.91 you have to include everything over 5 in the 1st 1 by (). ;)
thx l8er

-fire
 
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