How long will the football be in the air?
1 answer:
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Answer: Raymond is correct
The DJ charges $75 an hour.
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Explanation:
x = number of hours
y = total cost
The DJ does a 3-hour event for $275. This means one point is (x,y) = (3,275)
Another point is (5,425) because a 5-hour event costs $425.
Let's find the slope of the line through these two points.
The slope is 75, meaning that each time y goes up by 75, x goes up by 1.
Flipped around it means each time x goes up by 1, y goes up by 75.
This means each time we add on an extra hour, the cost goes up by $75.
The DJ charges $75 an hour. Raymond is correct.
The equation is 
.
We are looking for a function with a vertex above the x-axis and a function that opens upward (has coefficient a > 0).
The first function opens downward and intersects the x-axis. The second function has a vertex below the x-axis. The third function satisfies our requirements. The fourth function has a vertex on the x-axis.
We can solve this algebraically with the knowledge that the real solutions of a quadratic are its x-intercepts. If there are no x-intercepts (because it lies entirely above or below the x-axis), then there are no real solutions. This is true when the discriminant
. You can see that from the quadratic formula. This holds true for both answers A and C, so to find the correct one, we remember that when the coefficient a of the 
term is positive, the graph opens upwards, so we choose C.
We are looking for a function with a vertex above the x-axis and a function that opens upward (has coefficient a > 0).
The first function opens downward and intersects the x-axis. The second function has a vertex below the x-axis. The third function satisfies our requirements. The fourth function has a vertex on the x-axis.
We can solve this algebraically with the knowledge that the real solutions of a quadratic are its x-intercepts. If there are no x-intercepts (because it lies entirely above or below the x-axis), then there are no real solutions. This is true when the discriminant