The question is (x+2)^2= -5(y-1). I thought it would open up since the x^2 is positive but the answer says it opens down. I'm confused can someone please tell me how to figure out which way a parabola opens?
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(x + 2)² = - 5(y - 1)
- 5(y - 1) = (x + 2)²
- 5y + 5 = x² + 4x + 4
- 5y = x² + 4x + 4 - 5
- 5y = x² + 4x - 1
y = - 1/5 x² - 4/5 x + 1/5
The equation is y as a function of x, so the parabola opens vertically.
The sign of the coefficient of the x² term is negative, so it opens downward.
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- 5(y - 1) = (x + 2)²
- 5y + 5 = x² + 4x + 4
- 5y = x² + 4x + 4 - 5
- 5y = x² + 4x - 1
y = - 1/5 x² - 4/5 x + 1/5
The equation is y as a function of x, so the parabola opens vertically.
The sign of the coefficient of the x² term is negative, so it opens downward.
...
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hm...because of the -y most likely, if you think about it -y means it's being reflected about the x-axis(vertically)