A few days ago
babydollof4kids

# Find the axis of symmetry?

1. y=x^2+5x-7

2. y= -x^2-10x+7

A few days ago
?

these equations are parabolas..the second one is upside down…

so graph them (make a table)

then the axis of symmetry will go right through the vertex parallel to the y axis and will be writen in the from of x= ?

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A few days ago
Northstar
I’ll do the first one. The axis of symmetry goes thru the vertex and cuts the parabola in half.

Complete the square.

1. y = xÂ² + 5x – 7

y + 7 + 25/4 = xÂ² + 5x + 25/4

y + 53/4 = (x + 5/2)Â²

The vertex is (-5/2, -53/4).

The squared term is x so the parabola is vertical and the axis of symmetry will also be vertical. It’s equation is:

x = -5/2

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The second one works the same way.

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A few days ago
jeremy s
the easiest way to do this is to punch it into a graphing calculator like a Ti-83 or Ti-84. After you graph it if it is a mirror image in respect to the Y axis then the Y axis is the axis of symmetry. If it is a mirror image in respect to the X axis then it’s axis of symmetry is the X axis.

Also, since both equations appear to be quadratics they will both be symmetrical to the Y axis

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