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Friday, November 7, 2014

Solving Quadratic Equations of Two Unknowns, 3

Category: Algebra

"Published in Newark, California, USA"

Solve the following systems by elimination:



Solution:

Consider the given equations above  



Did you notice that 2x² will be eliminated if you will add the two given equations? Add the two equations in order to solve for the value of y.


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If y = 1, then the value of x is









If y = - 1, then the value of x is









Therefore, the solutions of the two equations are:  

 

Thursday, November 6, 2014

Solving Quadratic Equations of Two Unknowns, 2

Category: Algebra

"Published in Newark, California, USA"

Solve the following systems by substitution:



Solution:

Consider the given equations above 



Rewrite the second equation in terms of y at the left side as follows




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









By using quadratic formula, the values of x are


 
 
 

If you will choose the positive sign, then the value of x is





Substitute the value of x to the second equation in order to get the value of y, we have



 



If you will choose the negative sign, then the value of x is






Substitute the value of x to the second equation in order to get the value of y, we have 





Therefore, the solutions of the two equations are: