Question

Solve x

Answer 1

Step-by-step explanation:

$x^{2} - 4x - 7 = 0$

First, let's move the $7$ to the right-hand side so we can determine what constant we'll need on the left-hand side to complete the square:

$x^{2} - 4x = 7$

From here, since the coefficient of the $x$ term is $-4$, we know the square will be $(x - 2)$ (since $-2$ it's half of $-4$).

To complete this square, we will need to add $(-2)^{2}$ to both sides of the equation:

$x^{2} - 4x + (-2)^2 = 7 + ^{-2}$

$x^{2} - 4x + 4 = 7 + 4$

$(x - 2)^{2} = 11$

Now we can take the square root of both sides to figure out the solutions to $x$:

$x - 2 = \pm \sqrt{11}$

$x = 2 \pm \sqrt{11}$