How to complete the square to find the value of x?
To complete the square you compare your equation in the form x2 + bx + c = 0 to a similar equation of (x + b/2)2 + c = 0. From expanding out the second equation we have x2 + bx + (b/2)2 + c = 0 we can see this differs from the first equation by the term (b/2)2 so if we subtract (b/2)2 we are back to the original equation. So the equation x2 + bx + c = 0 is equal to (x + b/2)2 - (b/2)2 + c = 0. So to solve this we can move the terms around to get (x + b/2)2 = (b/2)2 - c which can then be solved by taking the square root of both sides.
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