<h3>
Answer: Table D</h3>
a = 8; b = 0; c = -8; parabola opens upward; y intercept at (0, -8)
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Reason:
The given equation is the same as y = 8x^2 + 0x - 8
Compare this to y = ax^2+bx+c
We see that
This rules out choice C because the a,b,c values don't match perfectly.
The parabola opens upward because a > 0, aka 'a' is positive. A positive 'a' value makes the parabola form a positive smile (in contrast to 'a' being negative to make a negative frown). This rules out choice A.
The y intercept always occurs when x = 0. Plug it in to get
y = 8x^2 - 8
y = 8(0)^2 - 8
y = -8
The y intercept is located at (x,y) = (0,-8). This rules out choice B.
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Summary:
We've found that
- a = 8, b = 0, c = -8
- parabola opens upward
- y intercept is at (0,-8)
All of these help us determine why choice D is the answer.
