# How do you solve y^2-7y-18=0?

May 21, 2018

See a solution process below:

#### Explanation:

We can factor the left side of the equation as:

$\left(y - 9\right) \left(y + 2\right) = 0$

Now, we can equate each term on the left to $0$ and solve for $y$:

Solution 1:

$y - 9 = 0$

$y - 9 + \textcolor{red}{9} = 0 + \textcolor{red}{9}$

$y - 0 = 9$

$y = 9$

Solution 2:

$y + 2 = 0$

$y + 2 - \textcolor{red}{2} = 0 - \textcolor{red}{2}$

$y + 0 = - 2$

$y = - 2$

The Solution Is: $y = \left\{- 2 , 9\right\}$