Find Where Undefined/Discontinuous f(x)=(x^2+2x)/(-4x+8)

$f (x) = \frac{x^{2} + 2 x}{- 4 x + 8}$

Set the denominator in $\frac{x^{2} + 2 x}{- 4 x + 8}$ equal to $0$ to find where the expression is undefined.

$- 4 x + 8 = 0$

Solve for $x$ .

Subtract $8$ from both sides of the equation.

$- 4 x = - 8$

Divide each term in $- 4 x = - 8$ by $- 4$ and simplify.

Divide each term in $- 4 x = - 8$ by $- 4$ .

$\frac{- 4 x}{- 4} = \frac{- 8}{- 4}$

Simplify the left side.

Cancel the common factor of $- 4$ .

Cancel the common factor.

$\frac{- 4 x}{- 4} = \frac{- 8}{- 4}$

Divide $x$ by $1$ .

$x = \frac{- 8}{- 4}$

Simplify the right side.

Divide $- 8$ by $- 4$ .

$x = 2$