Answer: Take it one step at a time. The chart should have x values close to 0, both positive and negative. You get the y-values by substituting for x and working out the calculation.
Explanation:
chart for y = -x² Remember you are squaring the (x) then multiply × -1 so all y-values are negative numbers.
x | y
-2 -4
-1 -1
0 0
1 -1
2 - 4
Plot those points on the graph, draw the parabola. It should look like the first graph attached. Since the vertex of the parabola is at the top, it is a maximum.
The parabola is a mirror image on either side of the y-axis, so that is the line of symmetry
Chart for y = x² –4 . figure x² first, then subtract 4
x . | . y
-2 0 . +4-2=0
-1 -3 +1 - 4 = -3
0 -4
1 -3
2 0
3 1 9 - 4 = 5
Your graph should look like the second (green) attached graph
I hope this is enough help for now.