Complete the square and then find the center and radius from the circle equation
2 answers:
Answer:
center: (2, -4); radius: 5
Step-by-step explanation:
Group x-terms and y-terms. Add the squares of half the coefficient of the linear term in each group. It can be convenient to subtract the constant, too.
(x^2 -4x) +(y^2 +8y) = 5
(x^2 -4x +4) +(y^2 +8x +16) = 5 + 4 + 16
(x -2)^2 +(y +4)^2 = 5^2
Comparing this to the form of a circle centered at (h, k) with radius r, we can find the center and radius.
(x -h)^2 +(y -k)^2 = r^2
(h, k) = (2, -4) . . . . . the circle center
r = 5 . . . . . . . . . . . . the radius
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Answer:
Step-by-step explanation:
Let
x -----> the number of minutes
y ----> the balloon's height in feet
we know that
The linear equation in slope intercept form is equal to
where
m is the slope
b is the y-coordinate of the y-intercept
In this problem we have that
The slope is equal to
----> is negative because is a decreasing function
Remember that the y-intercept is the value of y when the value of x is equal to zero
In this context the y-intercept is the height of the balloon when the time is equal to zero (initial height)
substitute