Answer:
B
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) = (3, - 20), thus
y = a(x - 3)² - 20
To find a substitute (7, 12) into the equation
12 = a(7 - 3)² - 20
12 = 16a - 20 ( add 20 to both sides )
32 = 16a ( divide both sides by 16 )
2 = a, thus
y = 2(x - 3)² - 20 ← expand using FOIL
y = 2(x² - 6x + 9) - 20 ← distribute and simplify
y = 2x² - 12x + 18 - 20
y = 2x² - 12x - 2 → B
