Find Where Undefined/Discontinuous (5x-10)/(x^2-4x+4)

$\frac{5 x - 10}{x^{2} - 4 x + 4}$

Set the denominator in $\frac{5 x - 10}{x^{2} - 4 x + 4}$ equal to $0$ to find where the expression is undefined.

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

Solve for $x$ .

Factor using the perfect square rule.

Rewrite $4$ as $2^{2}$ .

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

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$4 x = 2 \cdot x \cdot 2$

Rewrite the polynomial.

$x^{2} - 2 \cdot x \cdot 2 + 2^{2} = 0$

Factor using the perfect square trinomial rule $a^{2} - 2 a b + b^{2} = {(a - b)}^{2}$ , where $a = x$ and $b = 2$ .

${(x - 2)}^{2} = 0$

Set the $x - 2$ equal to $0$ .

$x - 2 = 0$

Add $2$ to both sides of the equation.

$x = 2$