Answers:
- Vertex form: y = -2(x-1)^2 + 8
- Standard form: y = -2x^2 + 4x + 6
Pick whichever form you prefer.
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Explanation:
The vertex is the highest point in this case, which is located at (1,8).
In general, the vertex is (h,k). So we have h = 1 and k = 8.
One root of this parabola is (-1,0). So we'll plug x = -1 and y = 0 in as well. As an alternative, you can go for (x,y) = (3,0) instead.
Plug those four values mentioned into the equation below. Solve for 'a'.
y = a(x-h)^2 + k
0 = a(-1-1)^2+8
0 = a(-2)^2+8
0 = 4a+8
4a+8 = 0
4a = -8
a = -8/4
a = -2
The vertex form of this parabola is y = -2(x-1)^2+8
Expanding that out gets us the following
y = -2(x-1)^2+8
y = -2(x^2-2x+1)+8
y = -2x^2+4x-2+8
y = -2x^2+4x+6 .... equation in standard form
20 possibilities based on this as a combination not a permutation, 6 nCr 3 = 20
Answer: No, it is not a solution
Work Shown:
-2 ≤ k/3
-2 ≤ -9/3
-2 ≤ -3
The last inequality is false because -3 should be smaller than -2 (not the other way around). Use a number line to help see this.
Since the last inequality is false, the original inequality must also be false for that particular k value. Therefore, k = -9 is not a solution.
Volume = pi*r^2
so 58^2*pi= 3364pi = approx 10,562.96 in^2
