SOLUTION: sketch the graph of the function. label the coordinates of the vertex. make sure to make your x & y table. then plot the points on the graph. 1) y=-x^2-4x+2 solve the equ

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Question 118550: sketch the graph of the function. label the coordinates of the vertex. make sure to make your x & y table. then plot the points on the graph.
1) y=-x^2-4x+2

solve the equation algebraically. check your solution by graphing. make sure to use an x &y table.
2)x^2-4=12
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
sketch the graph of the function. label the coordinates of the vertex. make sure to make your x & y table. then plot the points on the graph.
1) y = -x^2 - 4x + 2
:
First find the axis of symmetry (x= -b/(2a)) find the vertex from that and it
helps you choose the values for x when you make your x/y tables
:
In this equation: a = -1; b = -4
x = = = -2 is the axis of symmetry
:
Find the vertex, substitute -2 for x in the original equation:
y = -1(-2^2) - 4(-2) + 2
y = -4 + 8 + 2
y = +6
:
Vertex is -2,+6
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Choose the x values above and below x = -2
Substitute each value for x in the equation, you should get table like this
x | y
-------
-5 |-3
-3 |+5
-2 |+6; the vertex
-1 |+5
0 |+2; the y intercept
+1 |-3
:
Plot these x/y coordinates and your graph should look like this:
:

You can label the coordinates of the vertex: -2,+6
:
:
solve the equation algebraically. check your solution by graphing. make sure to use an x &y table.
2)
x^2 - 4 = 12
:
x^2 - 4 - 12 = 0; subtracted 12 from both sides:
:
x^2 - 16 = 0; recognize this as the "difference of squares"
:
Factors to:
(x-4)(x+4) = 0
:
x = +4 and x = -4
:
Make a table from x = -5 to +5, this will include the x intercepts
x| y
------
-5|+9
-4| 0; x intercept
-2|-12
0 |-16; the vertex
+2|-12
+4| 0; x intercept
+5|+9
:
Plot these and the graph should look like this:

:
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