Problem 1
To find the y intercept, plug in x = 0 and simplify
f(x) = (x-2)(x+4)
f(0) = (0-2)(0+4)
f(0) = (-2)*(4)
f(0) = -8
We have x = 0 pair up with y = -8
The y intercept is (0,-8)
Answer: Choice D
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Problem 2
(x-2)(x+4) is the same as x^2+2x-8 after using the FOIL rule. The distributive property is an alternate option.
The leading coefficient of x^2+2x-8 is 1. Since this leading coefficient is positive, it tells us that the parabola opens upward.
Answer: C) Parabola opens upward
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Problem 3
Answers:
Explanation:
Note that 1-x^2 is the same as -x^2+1 and this has a negative leading coefficient. So the parabola opens downward. That must mean curve C matches with function g(x).
Both f(x) and h(x) have the same leading term of x^2. However, the constant terms are different. Because f(x) has a smaller constant (-4 is smaller than 4) this makes curve B to be f(x), while curve A is h(x). The larger the constant is, the further shifted up the curve will be.
