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Graph the function using it vertex, axis of symmetry and intercepts f(x)=x^2+6x+9

0 votes

please help!

asked Dec 5, 2013 in ALGEBRA 2 by abstain12 Apprentice

2 Answers

0 votes

Given f(x) = x^2+6x+9

Compare it parabola equation y = ax^2+bx+c

a = 1, b = 6, c = 9

Axis of symmetry is x = -b/2a = -6/2*1 = -3

Axis of symmetry is x = -3.

Substitute x = -3 in given equation y = (-3)^2+6(-3)+9

y = 9-18+9

y = 0

Vertex of parabola is (x,y) = (-3,0)

To fnd y intercept substitute x = 0 in given equation.

y = x^2+6x+9 = 0+0+9 = 9

y intercept is 9.

To find x intercept substitute y = 0 in given equation.

0 = x^2+6x+9

x^2+3x+3x+9 = 0

x(x+3)+3(x+3) = 0

(x+3)(x+3) = 0

x+3 = 0 and x+3 = 0

x = -3 and x = -3

x intercept is -3.

Graph of parabola

Draw the coordinate plane.

plot the vertex of parabola and x intercepts and y intercepts.

Connect the points neatly ,sensitively like a curve.

Then ther is formed required parabola.

 

 

answered Dec 30, 2013 by david Expert
0 votes

The function f (x ) = x 2 + 6x  + 9

y  = x 2 + 6x + 9

The above equation represent a standard form of parabola = ax 2 + bx + c .

a  = 1, b  = 6, c  = 9

Axis of symmetry x  = -b /2a  = -6/2

Axis of symmetry = -3

Substitute x  value in = x 2 + 6x  + 9

y  = (-3)2 + 6(-3) + 9

= 0

Vertex of parabola (x , y ) = (-3, 0)

To find x intercept substitute y  = 0 in = x 2 + 6x  + 9.

0  = x 2 + 6x  + 9

(x + 3)2  = 0

x + 3 = 0

x = -3

So x  intercept is (-3, 0).

To find y  intercept substitute x = 0 in = x 2 + 6x  + 9.

  = (0) 2 + 6(0)  + 9

y  = 9

So intercept is (0, 9).

Graph

1.Draw the coordinate plane.

2.Plot the vertex , axis of symmetry and x , intercepts of parabola.

3.Then sketch the graph, connecting the points with a smooth curve.

answered May 21, 2014 by david Expert

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