Question

sqrt of (3x+4)=x

Answer 1

sqrt of (3x+4)=x

Raise both sides to the power of 2
3x+4=x^2
Move everything to the left and subtract x^2
-x^2+3x+4=0
Factor
(x-4)(x+1)
x = 4 x = -1
The answer is x = 4 which is non-extraneous and x = -1 is extraneous because it doesn't work if you plug it into the equation. Tim is technically correct because the SOLUTION is non-extraneous.

Am I on the right track?

Answer 2

Don't forget that the square of a sqrt is the absolute value of what's inside.

Answer 3

Non-extraneous confuses me s: if there are two solutions (like the following) and only one works, that one that works is NON-extraneous, right? and the one that is wrong is EXTRAneous, right?

Answer 4

You get |3x+4|=x^2 when you raise both sides to the power of 2.

Answer 5

After that you simply divide the problem into two cases, one where whats inside the absolute operator is below zero and one case where it's either 0 or above.

Answer 6

Not to tell you off, but I don't.
I checked my work with wolframalpha and I'm correct. There's no absolute value. Absolute value doesn't even correlate with my lesson

Answer 7

All I'm looking for is the extraneous part. I got the solving correct

Answer 8

Well, the extraneous part is derived from what I just said. (Not to tell you off :D )

Answer 9

That doesn't.. answer what I asked...

Answer 10

"Non-extraneous confuses me s: if there are two solutions (like the following) and only one works, that one that works is NON-extraneous, right? and the one that is wrong is EXTRAneous, right?"

Answer 11

I'm not sure what extraneous means, if it means that the value belongs to the domain of the function; yes.

Answer 12

Why are you in here if you don't know what it means :( Gooooosh

Answer 13

Is your question what the word extraneous means? If so, it means that something is not constituting a vital element.

Answer 14

Yeah, I know because "extra" .-. I guess I'm just trying to word it in a different manner due to my original question on my test.

Answer 15

The reason I don't know what it means is because I'm not native English; nor did I learn math strictly from English definitions -- but from Swedish.

Answer 16

It's cool. You explained it just in a... more in depth way. I suppose I got my answer.