# How do you solve x^2 - 9x - 10 = 0?

Jun 23, 2015

color(green)( x= -1 , x=10

#### Explanation:

${x}^{2} - 9 x - 10 = 0$
We can first factorise this expression and then proceed towards finding the solution:

factorising by : splitting the middle term
${x}^{2} \textcolor{b l u e}{- 9 x} - 10 = 0$
${x}^{2} \textcolor{b l u e}{- 10 x + x} - 10 = 0$
$x \left(x - 10\right) + 1 \left(x - 10\right) = 0$
$\textcolor{g r e e n}{\left(x + 1\right) \left(x - 10\right)} = 0$

Equating the factors with zero to obtain solutions:
$x + 1 = 0$ and $x - 10 = 0$

So, the solutions are:
color(green)( x= -1 , x=10