Need some help here.
1
Name:
Anonymous
2007-12-29 21:06
Okay, math nerds.
I'm trying to solve this math problem. I'm trying to tutor someone, and this problem is really stumping me. Any help?
3x^2 – 2x + 7 = 0, then (x-1/3)^2 = ?
I need the answer in a fraction, and how you arrived at that answer.
2
Name:
Anonymous
2007-12-29 22:02
First, use the quadratic formula to find the solutions, and then substitute the answers into (x-1/3)^2 to find the answer.
3
Name:
Anonymous
2007-12-29 23:53
The quadratic gives me
[2 +- sqrt(-80)]/6]
which is imaginary. I'm starting to think maybe the question was misprinted.
4
Name:
Anonymous
2007-12-30 0:12
No problems, if it is an imaginary root, then use this imaginary root.
5
Name:
Anonymous
2007-12-30 0:33
Alright. Let's use [2 + sqrt(-80)]/6 first. That's
[2 + 4sqrt(-5)]/6
Or
2/6 + 4sqrt(-5)/6
Or
1/3 + 2sqrt(-5)/3
Plugged into the second equation, that's
[1/3 + 2sqrt(-5)/3 - 1/3]^2
Which is
[2sqrt(-5)/3]^2
Which is (4*-5)/9, or -20/9, which is one of the answers on the sheet. Holy crap, that took forever. Thanks.
6
Name:
Anonymous
2007-12-30 2:32
>I'm trying to tutor someone
7
Name:
Anonymous
2007-12-30 2:36
It's been a couple of years. I'm rusty. Right now we're covering adding and subtracting fractions. I'm getting familiar with the difficult stuff now, so I can be prepared when we get to it.
8
Name:
Anonymous
2007-12-30 17:14
>I'm getting familiar with the difficult stuff now
lol wut
9
Name:
Anonymous
2007-12-30 17:36
>>7
>difficult
Lol idiot. Can't even do any geodesics.
10
Name:
Globbo
2007-12-30 18:46
>>5
Here's a much easier solution.
We want to know (x - 1/3)^2.
Let's call this y. We want to find y. Then:
y = (x - 1/3)^2
y = x^2 - 2/3 x + 1/9
3y = 3x^2 - 2x + 1/3
3y + 20/3 = 3x^2 - 2x + 7
But the right-hand side of this last equation was given to be zero. So we have:
3y + 20/3 = 0
y = -20/9
Do I get the prize?