# How do you solve the quadratic using the quadratic formula given n^2=9n-20?

Nov 4, 2016

$n = 4$ and $n = 5$

#### Explanation:

${n}^{2} = 9 n - 20$

Take all the terms to the left.

${n}^{2} - 9 n + 20 = 0$

Factorise the equation.

${n}^{2} - 5 n - 4 n + 20 = 0$

$n \left(n - 5\right) - 4 \left(n - 5\right) = 0$

$\left(n - 4\right) \left(n - 5\right) = 0$

$n - 4 = 0$ and $n - 5 = 0$

$n = 4$ and $n = 5$