



 
Hi Julie, I am going to illustrate using the equation x^{2}  8x = 15. The instructions again are to solve for x by completing the square. The key to solving this problem is recognizing a pattern. Examine the two expressions
In each case if you know the coefficient of x, + 2a or 2a, take half of it and square the result you get the constant term a^{2}. (This observation is only true if the coefficient of x^{2} is 1.) Thus in my example where the coefficient of x is 8, half of it is 4 and (4)^{2} = 16. Thus x^{2}  8x + 16 is a square (x  4)^{2}. So here is how I proceed to solve the problem.
I hope this helps,  


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