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Friday, November 14, 2014

Solving Cubic Equations of Two Unknowns

Category: Algebra

"Published in Newark, California, USA"

Solve the following systems by substitution:



Solution:

Consider the given equations above 



The first equation can be factored by the sum of the two cubes as follows



But

Hence, the above equation becomes



 
The second equation can be written as
 
 
 

Substitute the value of y to the above equation, we have
 
 
 
 
 
 

By using completing the square method, the value of x is
 







If , then y equals





If , then y equals
 




Since the solutions of the two equations have imaginary numbers or complex numbers, then the two equations have no solution.