Question

Solve the quadratic equation by completing the square. x2 + 4x - 3 = 0

Answer 1

First move the constant to the other side of the equation by adding 3 to both sides...

x^2+4x=3

Now halve the linear coefficient, 4/2=2, square it, 2^2=4, and add that value to both sides...

x^2+4x+4=7, now the left side is a perfect square of the form...

(x+2)^2=7, now take the square root of both sides...

x+2=±√7,  subtract 2 from both sides...

x=-2±√7

So x=-2-√7 and -2+√7