jakeagilbert

02.06.2021 • 

Mathematics

Balloon Elevation 460-
Think About the Process Why is a data point with an
x-coordinate of O a good point to use when creating a trend
line for a data set? The graph shows the altitude of a
weather balloon over time. The trend line passes through the
points (0,436) and (10,342). Write the equation of a trend line
for the data shown in the graph. After how many minutes is
the balloon at an altitude of 351.4 feet above sea level?
Altitude (ft)
390-
320+
Why is a data point with an x-coordinate of 0 a good point to use when creating a trend line for a
data set? Select all that apply.
DA. It is easy to compute the slope using this point.
B. The coordinates of this point are both 0.
C. The y-coordinate of this point is always positive.
D. The y-coordinate of this point is the y-intercept.

Ответ:

TheViperMlg23676

12.02.2023

Mathematics

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525 = (w+4)(w)21 ft by 25 ft

Step-by-step explanation:

Let w represent the width of the floor. Then the length of the floor is (w+4) and its area is ...

  A = LW

  525 = (w+4)(w)

  w^2 +4w -525 = 0

  (w -21)(w +25) = 0 . . . . factor the above

Solutions are ...

  w = 21, w = -25

We are interested in the positive solution: w = 21.

The floor is 21 feet wide and 25 feet long.

Alternate solution

Sometimes, when the factors aren't obvious, it works well to write an equation for the average of the dimensions. Here, we can represent that with x, and use (x-2) for the width, and (x+2) for the length. Then we have ...

  525 = (x-2)(x+2) = x^2 -4

  529 = x^2

  √529 = 23 = x

Then w=23 -2 = 21, and the length is w+4 = 25.

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