Question

Which is the correct answer?

Answer 1

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