Answer:
y = x² - 4x - 21
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k) = (2, - 25), thus
y = a(x - 2)² - 25
To find a substitute (7, 0) into the equation
0 = a(7 - 2)² - 25 = a(5)² - 25 = 25a - 25 ( add 25 from both sides )
25a = 25 ( divide both sides by 25
a = 1, thus
y = (x - 2)² - 25 ← in vertex form
Expand and simplify
y = x² - 4x + 4 - 25
y = x² - 4x - 21 ← in standard form
