Answer:
- y-intercept: 58
- vertex: (2, 78) -- a maximum
Step-by-step explanation:
The negative leading coefficient tells you this parabola opens downward, so the vertex will be a maximum. The constant is the y-intercept, which is 58.
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The vertex is nicely found using a graphing calculator, but can also be found algebraically. The x-value is ...
x = -b/(2a) = -19.8/(2·(-4.9)) = 19.8/9.8 = 99/49 ≈ 2.02041
The value of f(99/49) is ...
f(99/49) = (-4.9(99/49) +19.8)(99/49) +58 = (9.9)(99/49) +58 ≈ 78.002
The location of the vertex is approximately ...
(x, y) ≈ (2.0204, 78.002) ≈ (2, 78)
