Answer:
not really sure for number one
1. 1.56y × 3.9x
2. 4.8x + 9.6y
Answer:
The proportion of students whose height are lower than Darnell's height is 71.57%
Step-by-step explanation:
The complete question is:
A set of middle school student heights are normally distributed with a mean of 150 centimeters and a standard deviation of 20 centimeters. Darnel is a middle school student with a height of 161.4cm.
What proportion of proportion of students height are lower than Darnell's height.
Answer:
We first calculate the z-score corresponding to Darnell's height using:

We substitute x=161.4 ,
, and
to get:

From the normal distribution table, we read 0.5 under 7.
The corresponding area is 0.7157
Therefore the proportion of students whose height are lower than Darnell's height is 71.57%
What is this question supposed to be?
the second one? Step-by-step explanation:
The graph of the circle equation is graph (d)
<h3>How to determine the circle?</h3>
The equation is given as:
x^2 + y^2 - 4x + 9y -7 = 0
Rewrite as:
x^2 - 4x + y^2 + 9y = 7
Express (x^2 - 4x) and (y^2 + 9y) as perfect squares.
So, we have:
(x - 2)^2 + (y + 3)^2 = 7 + 4 + 20.25
Evaluate the sum
(x - 2)^2 + (y + 3)^2 = 31.25
A circle equation is represented as:
(x - h)^2 + (y - k)^2 = r^2
Where
Center = (h, k)
Radius = r
So, we have:
(h, k) = (2, -3)
r^2 = 31.25
r = 5.5
The circle that has a center of (2, -3) and a radius of 5.5 is graph d
Hence, the graph of the circle equation is graph (d)
Read more about circle equation at:
brainly.com/question/1559324
#SPJ1