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# Helppp how to solve x=5√(x) - 6 watch

1. (Original post by KittyRe-play)
But then using the y method the solutions are x=3 & x=2 and it's not the same as 4 and 9. So is that incorrect?
no, using the y-method you got y=3 and y=2
2. (Original post by TenOfThem)
no, using the y-method you got y=3 and y=2
Yeah so why do you square them up to get 4 and 9? Is it because y^2=x? What is this general formula I've never come across it before?
3. (Original post by KittyRe-play)
Yeah so why do you square them up to get 4 and 9? Is it because y^2=x? What is this general formula I've never come across it before?
I do not know what formula you are referring to

The equation was

You chose to solve

Can you not see how they are linked
4. (Original post by TenOfThem)
I do not know what formula you are referring to

The equation was

You chose to solve

Can you not see how they are linked
No I can see how they are linked. Basically you have replaced x with y squared. But how can you just plug y squared in out of nowhere is what I'm asking, like it must be a formula or something right?
5. the equation, when everything is put on the LHS, is what is termed a "disguised quadratic" - as its just that - a quadratic, in some variable, in disguise.

you can either, choose method 1). re-arranging and squaring, which may or may not introduce entraneous solutions,

or method 2). as TenOfThem has explained, use something like , solve for p, and then square the result, then check in the original equation.
6. (Original post by Hasufel)
the equation, when everything is put on the LHS, is what is termed a "disguised quadratic" - as its just that - a quadratic, in some variable, in disguise.

you can either, choose method 1). re-arranging and squaring, which may or may not introduce entraneous solutions,

or method 2). as TenOfThem has explained, use something like , solve for p, and then square the result, then check in the original equation.
So is some sort of formula? Like a general formula? What is it specifically used for?
7. (Original post by KittyRe-play)
So is some sort of formula? Like a general formula? What is it specifically used for?
Nah, just a general substitution which is "convenient" for transforming this particular equation into a quadratic.

you should, at that stage, be practiced enough to recognise that theres a convenient substitution:

(or r, s t, or any other "arbitrary" letter you choose to solve the quadratic for)

so you get:

solve for p, then as the substitution demands, take natural logs to solve for x,,,
8. (Original post by Hasufel)
Nah, just a general substitution which is "convenient" for transforming this particular equation into a quadratic.

you should, at that stage, be practiced enough to recognise that theres a convenient substitution:

(or r, s t, or any other "arbitrary" letter you choose to solve the quadratic for)

so you get:

solve for p, then as the substitution demands, take natural logs to solve for x,,,
Thanks man that makes so much sense now.

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