Question 914732
The sum of two numbers is 210.
 If one number is the square of the other, find the set of numbers.
:
x^2 + x = 210
x^2 + x - 210 = 0; a quadratic equation
Factors to
(x-14)(x+15) = 0
the positive solution
x = 14, x^2 = 196;  196 + 14 = 210
:
x = -15 also works 
-15^2 = +225 - 15 = 210