How do I complete the square?
Completing the square is an algebraic method that can be used to solve a quadratic equation and find the coordinates of a turning point of a graph. Let's use x2 + 4x -5 = 0 are our example.First, half the coefficient of x, 4/2 =2 .Put this value inside brackets: (x +2), and square the brackets (x+2) 2Then, you need to subtract the square of the number you put in brackets, in this case 22 = 4 , so (x +2)2 -4 .Lastly, you just copy on the end the original third term, for us this is -5: (x+2)2-4 -5 This simplifies to (x +2)2 -9 =0 From this you can solve the equation for x (x= 1 or -5 ) and determine the coordinates of the turning point (-2,-9 )
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