To find the equations that represent parabolas, we need to identify equations of the form \( y = ax^2 + bx + c \), where \( a \) is not equal to zero. A parabola opens upwards or downwards depending on the sign of \( a \).
Let's evaluate each of the provided equations:
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\( y = -4x^2 \)
- This is a parabola that opens downward (since \( a = -4 < 0 \)).
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\( y = 16x + 6 \)
- This is a linear equation (not a parabola), as it can be written as \( y = 0x^2 + 16x + 6 \) (where \( a = 0 \)).
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\( y = 2^x \)
- This is an exponential equation (not a parabola).
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\( y = 8x \)
- This is also a linear equation (not a parabola), as it can be written as \( y = 0x^2 + 8x \) (where \( a = 0 \)).
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\( y = (-9)^x \)
- This is another exponential equation (not a parabola).
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\( y = 6x^2 \)
- This is a parabola that opens upward (since \( a = 6 > 0 \)).
Based on this analysis, the equations that represent a parabola are:
- \( y = -4x^2 \)
- \( y = 6x^2 \)
So, the responses that represent parabolas are:
- y = −4x^2
- y = 6x^2