How do you graph #y = x² + 2x – 4#?

1 Answer
Nghi N.
Aug 16, 2015

Graph y = x^2 + 2x - 4

Explanation:

To graph a parabola, find a few critical points:
Axis of symmetry --> #x = -b/2a = - 1#
Vertex --> #x = -b/2a = -1#
y = f(-1) = 1 - 2 - 4 = -5
y-intercept --> make x = 0 --> y = -4
x-intercept --> solve y = 0 --> #x^2 + 2x - 4 = 0.#
#D = d^2 = b^2 - 4ac = 4 + 16 = 20 #--># d = +- 2sqrt5#
#x = -2/2 +- 2sqrt5/2= -1 +- sqrt5#
graph{x^2 + 2x - 4 [-10, 10, -5, 5]}

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