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15 votes
15 votes
Determine the rule of a quadratic function in factored

form given the following information:
.
the zeros are (-2,0) and (4,0)
it passes through the point (5,14)
.

User Levent Tulun
by
3.0k points

1 Answer

25 votes
25 votes

Answer:


y=2(x+2)(x-4)

Explanation:

Hi there!

Factored form:
y=a(x-r)(x-s) where r and s are two zeros

Given that the zeros are (-2,0) and (4,0), we know that -2 and 4 are r and s in the above equation. Plug these in:


y=a(x-(-2))(x-(4))\\y=a(x+2)(x-4)

Now, to solve for a, plug in the given point (5,14) as (x,y):


14=a(5+2)(5-4)\\14=a(7)(1)\\14=7a\\a=2

Therefore, a=2. Plug this back into the original equation:


y=2(x+2)(x-4)

I hope this helps!

User Alfian Busyro
by
3.5k points