1. y=x^2+5x-7
2. y= -x^2-10x+7
2007-07-09 18:53:48 · 3 answers · asked by babydollof4kids 1 in Education & Reference ➔ Homework Help
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= ?
2007-07-09 19:08:09 · answer #1 · answered by ? 4 · 0⤊ 0⤋
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 = x² + 5x - 7
y + 7 + 25/4 = x² + 5x + 25/4
y + 53/4 = (x + 5/2)²
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
_________________
The second one works the same way.
2007-07-10 05:15:14 · answer #2 · answered by Northstar 7 · 0⤊ 0⤋
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
2007-07-10 02:10:29 · answer #3 · answered by jeremy s 2 · 0⤊ 0⤋