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+----- Thread: Need help with a maths problem (/showthread.php?tid=20383)
Need help with a maths problem - Zeon - 07-10-2011
x^2 + 3x +2 = (x+2)(x+a) Find a.
Can someone explain how to do it?
RE: Need help with a maths problem - BlackChaos - 07-10-2011
First of all, you need simplify the equation:
x^2 + 3x + 2 = x^2 + ax + 2x + 2a
Then, we bring the variable to one side and the numerical values on the other side by transposing them:
x^2 + 3x - x^2 - ax -2x - 2a = -2
By simplifying further, we get:
x - ax = -2
-x + ax = 2
Now we try to bring x to right hand side:
a = (2 + x)/x
This is the solution for a in terms of x. If you have the value of x, then you can find the value of a as well.
Hope this helps.
RE: Need help with a maths problem - AceInfinity - 07-10-2011
This is a trinomial which can be turned into a binomial. You'd never really do it the way that BlackChaos showed you.
BlackChaos is unfortunately wrong. Solving for "a" means solving for a value, that value can be anything since you haven't solved for X yet.
The answer for the value of a is actually 1.
![[Image: idJmyC.png]](http://k.min.us/idJmyC.png)
RE: Need help with a maths problem - BlackChaos - 07-10-2011
(07-10-2011, 04:14 AM)Ace Wrote: This is a trinomial which can be turned into a binomial. You'd never really do it the way that BlackChaos showed you.
BlackChaos is unfortunately wrong. Solving for "a" means solving for a value, that value can be anything since you haven't solved for X yet.
The answer for the value of a is actually 1.
Spoiler (Click to View)
I knew I was overlooking something. I should have converted it to a binomial equation first.
RE: Need help with a maths problem - AceInfinity - 07-10-2011
Not bad though, good try at the attempt, and your advice to simplifying the equation is accurate, but you need to simplify the sides of the equation first before you combine them.
Teaching 2 members in one post lol
I hope you both know what "FOIL" is...
"First" "Inside" "Outside" "Last" ?
It's the way you would convert a binomial to a trinomial, therefor it can be used in reverse to do the opposite.
RE: Need help with a maths problem - BlackChaos - 07-10-2011
(07-10-2011, 04:42 AM)Ace Wrote: Not bad though, good try at the attempt, and your advice to simplifying the equation is accurate, but you need to simplify the sides of the equation first before you combine them.
Teaching 2 members in one post lol
I hope you both know what "FOIL" is...
"First" "Inside" "Outside" "Last" ?
It's the way you would convert a binomial to a trinomial, therefor it can be used in reverse to do the opposite.
Of course.
I took Maths as my +2 option, but this is honestly just the second time I've tried solving Maths problems on the forum. Thanks for the correction bro.
RE: Need help with a maths problem - AceInfinity - 07-10-2011
No problem, i'm good with numbers and algebra as it's required for programming in some way as well lol. Especially C++ where algebra is almost like a sub-native language to it.
Assigning values to letters, and then adding letters in a sequence, is all possible. variables like that change a lot which is why it's easier to use variables in that way with C++. Variables can change an infinite amount of times within execution.
RE: Need help with a maths problem - AsSaSs@iN - 07-11-2011
lol BlackChaos, you over thought. I did it in 2 lines.. But don't we all do that from time to time, I got a very simple quadratic question wrong in my exam (Q1.a. most easy question). Yet Q10.c the hardest, correct xD
RE: Need help with a maths problem - BlackChaos - 07-12-2011
I wasn't trying to solve it myself. I was trying to explain it to the OP. That's why ended up messing up.
RE: Need help with a maths problem - Mayhem - 07-12-2011
(07-12-2011, 12:23 AM)BlackChaos Wrote: I wasn't trying to solve it myself. I was trying to explain it to the OP. That's why ended up messing up.
Explaining and giving the answer is good, but it means if you make a mistake in either you messed up the point of it. Though what you tried to do is a good thing.