2(a-b) is worked out as 2 times (a minus b). a and b are the same value, so it works out at 2 times (0), equaling 0, not 2. and a plus b minus 2b is worked out as (a + b) – 2b. since a nd b are the same value, (a + b) can be sated as 2b, or 2a, doesn’t matter. so it will work out as 2b – 2b, which equals 0
and 0 = 0 last time i checked. am i right?

After the third to last line they simplify ‘a + b – 2b’ to ‘a – b’, That’s valid. They then divide each side by (a-b). That’s valid too. I’m sure there’s an error, but it’s some inexplicable algebra ‘rule’ and I can’t find it.

Kella .. if you divide by (a – b) in the second to last line you don’t get 1 on the right side. You get (a / (a – b)) – (b / (a – b)). This is because both a & b would get divided separately by the (a – b). So everyone is right that this is stupid.

Yeah, a bunch of these people already said it, but in case anyone didn’t understand: if a=b, then a-b=0. This is fine, but in the 2nd to last line, we divide both sides by a-b, and since a-b=0 we’re dividing by zero, which isn’t allowed in math.

anonymous

10:34 pmYou’d have to be an idiot to believe this. The second-to-last row equals 0 on both sides, so where the hell does “2=1″ come from?

Jay-Cee

10:48 pm2(a-b) is worked out as 2 times (a minus b). a and b are the same value, so it works out at 2 times (0), equaling 0, not 2. and a plus b minus 2b is worked out as (a + b) – 2b. since a nd b are the same value, (a + b) can be sated as 2b, or 2a, doesn’t matter. so it will work out as 2b – 2b, which equals 0

and 0 = 0 last time i checked. am i right?

calo

10:50 pmFalse. Just substitute in any number

???

10:57 pmIf a=b, then (a-b)=0. Therefore, 2(a-b)=0 and a-b=0, so 0=0, not 2=1.

Paul

11:18 pmThe last operation is not a viable operation.

Sammy

11:47 pmYou just randomly took out the -2b Nice try though!!

Kella

12:07 amAfter the third to last line they simplify ‘a + b – 2b’ to ‘a – b’, That’s valid. They then divide each side by (a-b). That’s valid too. I’m sure there’s an error, but it’s some inexplicable algebra ‘rule’ and I can’t find it.

Jarom

12:28 amYou can’t divide by zero. Which is what a minus b is. Therefore the last operation isn’t valid.

Fresh

12:28 amKella .. if you divide by (a – b) in the second to last line you don’t get 1 on the right side. You get (a / (a – b)) – (b / (a – b)). This is because both a & b would get divided separately by the (a – b). So everyone is right that this is stupid.

Anon

12:37 ama=b. a-b=0. (a-b) divided by (a-b) is dividing by 0, which is always unallowed.

Mateo

12:39 am(a-b)/(a-b) is not valid, it’s 0/0.

Anonymous

1:40 amYeah, a bunch of these people already said it, but in case anyone didn’t understand: if a=b, then a-b=0. This is fine, but in the 2nd to last line, we divide both sides by a-b, and since a-b=0 we’re dividing by zero, which isn’t allowed in math.