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Prince Mark Alvarez
Nov 15, 2020
  ·  Edited: Nov 15, 2020

How do I find its inverse

I was revisiting functions and its inverse.


I am stuck finding th inverse of:

y = x^2+5/25x


Update:

x=y^2+5/25y

25x = (y^2 +5)/y





Any ideas to how to continue to solve it?

3 answers0 replies
2
Jack Merrin
Nov 15, 2020

solve for y which is the inverse

x = y^2 +5/25y

2
Phinehas
Nov 24, 2020

First of all, is y in the denominator of 5/25y or is 5/25 just the coefficient of y?

Second of all, I don't understand how you got 25x = (y^2+5)/y, if you multiplied x = y^2+5/25y by 25, then y^2 should have a coefficient of 25 as well since it wasn't in the numerator.

2
Phinehas
Nov 24, 2020

It seems to me that you're trying to find the formula for y from x=y^2+1/5y.

Then a quadratic equation is enough. Just bringing the x as a constant in terms of y we get y^2+1/5y-x = 0 which gives by the quadratic formula: y = (-1/5+sqrt(1/25+4x))/2 and (-1/5-sqrt(1/25+4x))/2 as the 2 roots. That's your answer