Question 162320
find the real solution to the equation 9x^2=30x-25 let u=x^2 
i substitute u for x^2 so I get 9u but then do I make 30x square root of 30x and move it and 25 to the other side of the equation after that? or use the power principle? confused thank you
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That substitution won't help.  Use the quadratic solution.
9x^2=30x-25 
9x^2 - 30x + 25 = 0
*[invoke solve_quadratic_equation 9,-30,25]

Or, take the sqrt of both sides:
9x^2 - 30x + 25 = 0
(3x-5)^2 = 0
3x-5 = 0
x = 5/3  Only one answer, since +0 and -0 are the same.
email me with any questions about this.