Simple question involving simplification

[oceanplexian]

Ok, I just did out a problem

(3X-1)^2+(3X-1)-12=0

foiled it and came up with

[ 3 +/- sqrt(441) ] / 18

after putting it into the quadratic formula.

err..I get confused here when simplifying the square root of 441

I was thinking of simplifying it to 9*sqrt(49) which is 63
but I don't think that's correct, any tips?

thanks,
oceanplexian

 

[ChaoticLlama]

(3X - 1)² + (3X - 1) - 12 = 0

An easier method to solve this problem is to make a substitution.
For example... let z = 3x - 1

z² + z - 12 = 0

That quadratic looks much nicer. Simply factor the new 'z' quadratic, and then put x back into the equation, and you're done without having to expand.

 

[oceanplexian]

thanks

I didn't even notice that I could substitute...thanks for saving me from doing a ton of work.


-oceanplexian