Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
You are not logged in.
Post a reply
Topic review (newest first)
Follow this link and learn how to complete the square.
Ahhh... so because -c/a have "no value" or are just equal to 1, we can manipulate them how we want?
Well you could multiply by 7/7 or xyz/xyz or 4pq/4pq
I get that we're supposed to multiply -c/a by 4a/4a, but I'm not seeing where that 4a/4a is coming from.
Why nog justmultiply the top and the bottom of the fraction by 4 like Bob said?
Ah I'm sorry bob, but I don't think you're getting what I'm trying to say. I think I have a better way to explain it, check this out.
Ok, don't worry. I'll try to sort that out. It is an algbra misunderstanding. When I have trouble with algebra, I go back to some numbers and try the same thing.
Let's say that c = 3, b = 12 and a = 5
Now, if you have two fractions to add together, you have to make the denominators the same. I want both /100
So multiply the fraction by 4 x 5
Now with letters
Ah, so let me try something here.
Yout aren't multiplying by 4A but rather multiply by 4A / 4A. Which is the same as multiplying by 1.
I actually watched a video that explained it that way. I'm still confused on one thing though, I want to know where the 4a that we multiply -c/a comes from. That's what I'm trying to figure out. The 4a we multiply against -c/a can't just come from nowhere right? Nothing in math can just come from "thin air" right? I mean we can't just say "We're going to multiply -c/a by 4a just because", that 4a has to come from some process and that's what I want to know.
OK, so carrying on from there:
Then put all over this denominator and re-arrange.
Then you can square root everything. Only one +/- sign is needed in the final expression.
Take the b/2a term across to the right hand side, all over the same denominator.
Hopefully that sorts it out for you.
Alright let me start from the beginning.
What I do here first is I move the "loose" number over to right.
Now we have
Now I take the coefficient on and divide it through the entire equation.
Now my method tells me that I take half of the middle term, square it and then add it to both sides.
We end up with this.
This is where I got stuck. I don't know how to get the common denominator of 4a for -c/a. I hope I wrote everything out correctly as I was doing this through memory, and keeping track of exponents and what not can be a little tough when typing it out lol.
Thanks guys. I was learning to do this through a different slightly different method however, and even though this method looks a bit shorter I'd prefer to stick with what I'm already familiar with . If you could explain how -c/a gets the common denominator of 4a in my version of the problem bob that'd be great .