answer:
Example:
Write the equation of the axis of symmetry, and find the coordinates of the vertex of the parabola y=−3x2−6x+4.
The equation of the axis of symmetry for the graph of y=ax2+bx+c.
x=−b2a
Substitute −3 for a and −5 for b in the equation of the axis of symmetry.
x=−−62(−3) =−1
So, the equation of the axis of symmetry is x=−1.
Since the equation of the axis of symmetry is x=−1 and the vertex lies on the axis, the x-coordinate of the vertex is −1.
To find the y-coordinate of the vertex, first substitute −1 for x in the given equation.
y=−3(−1)2−6(−1)+4
Simplify.
y=−3+6+4 =7
Therefore, the coordinates of the vertex of the parabola is (−1,7).
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