To find the equation of a perpendicular line, you first need to find the negative reciprocal of the slope given. The slope is -1/3, so the slope of the perpendicular line will be 3
Now we just need to find the y intercept using the point (3, 2) and you can plug the coordinates in and then solve for b. Let's see what that looks like.
y=3x+b
2=3*(3)+b
2=9+b
-7=b So now we know the y-intercept and slope. We just put them together now
y=3x-7
<span>4x(5y-x)-5y(4x-y)=20xy-4x^2-20yx+5y^2=-4x^2+5y^2=5y^2-4x^2</span>
To solve this problem, we use the formula:
z = (x – u) / s
where z is the z score value which can be obtained from
the tables, x is the sample value, u is the mean = 6.3 min, and s is the std
dev = 2.2 min
at P value = 0.90, the z = 1.28, finding for x:
x = z s + u
x = 1.28 * 2.2 + 6.3
x = 9.116
at P value = 1.0, the z = 3.49, finding for x:
x = z s + u
x = 3.49 * 2.2 + 6.3
x = 13.978 ~ 14
Therefore the longest 10% calls last about 9.1 minutes to
14 minutes
418+14
The other ones all add up to 42
Hope this helps!