The quadratic function, with intercepts at -5, 1, and 5, is y = 0 in intercept form. In standard form, after expanding, it is y =

a. Intercept Form:
The quadratic function in intercept form is given by y = a(x - p)(x - q), where p and q are the x-intercepts.
1. X-intercepts (roots): Set y = 0 to find intercepts. Roots are x = -5, 1, 5.
2. Equation:
y = a(x + 5)(x - 1)(x - 5)
3. Substitute a point (e.g., x = 3, y = 0):
![\[ 0 = a(8)(4)(-2) \implies a = 0 \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/miz8puhn4a9xf5oaelh191gg2ywbz89n32.png)
4. Final Equation:
y = 0 (This quadratic has roots but no vertical stretch; it's a straight line)
b. Standard Form:
The standard form of a quadratic is

1. Expand Intercept Form:
![\[ y = a(x + 5)(x - 1)(x - 5) \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/rwd3tew9if3ix97bdsuf1ja8bs5ag5shoj.png)
![\[ y = a(x^3 - x^2 - 19x + 25) \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/xtdm2v69b81x34x9d3vx17fp7mkahdwxnu.png)
2. Substitute another point (e.g., x = -6, y = 9):
![\[ 9 = a(-216 + 36 + 114 + 25) \implies a = (4)/(5) \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/q4oru4wvhre58kr5qxqnf4uwlhr4dyrm7h.png)
3. Final Equation:
![\[ y = (4)/(5)x^3 - (4)/(5)x^2 - (76)/(5)x + 5 \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/titbjjjcvj4lm70wa9bz12uryjfrs05fp9.png)