Question 971209
I will restart but not complete this:

The question number was from this:  http://www.algebra.com/algebra/homework/quadratic/Quadratic_Equations.faq.question.971204.html


A man is x^2 age while his son is x years of age.
In 4x years, the man will be twice as old as his son.


m and s for MAN and SON, their present ages.


{{{system(m=x^2, s=x,m+4x=2(s+4x))}}};


Substitute for m and s in the "4x" equation.
{{{x^2+4x=2(x+4x)}}}
which is an unsimplified quadratic equation in just the one variable, x.


This can be simplified, put into general form, and then solved for x.