# How do you write a quadratic function in intercept form whose graph has x intercepts 0, 4 and passes through (-1, 20)?

Jun 12, 2017

$y = 4 x \left(x - 4\right)$

#### Explanation:

$\text{since the x-intercepts are " 0" and } 4$

$\text{then factors are " (x-0)" and } \left(x - 4\right)$

$\Rightarrow y = a x \left(x - 4\right)$

$\text{to find a substitute " (-1,20)" into the equation}$

$20 = a \left(- 1\right) \left(- 5\right) \Rightarrow a = \frac{20}{5} = 4$

$\Rightarrow y = 4 x \left(x - 4\right) \leftarrow \textcolor{red}{\text{ in intercept form}}$