Double the second equation (multiply by 2)...
2(x-2y=10)
2x-4y=20
Bring in the second equation and add the equations:
(2x-4y=20)
+ (5x+4y=8)
7x=28
x=4
Plug in x into one of the equations to get y...
(4)-2y=10
-2y=6
y=-3
(6,-3)
Make sure to follow me!
Subtract 5 from both sides.
49 - 5 = 44
11q ≤ 44
Divide both sides by 11.
44/11 = 4
q ≤ 4
Cos x = -12/13
sin x = -sqrt(13^2 - 12^2) / 13 = -5/13
tan x = 5/12
tan x/2 = (1 - cos x) / sin x = 1 - (-12/13) / -5/13 = 25/13 * -13/5 = -5
2sin^2 x/2 = 1 - cos x = 1 - (-12/13) = 25/13
sin^2 x/2 = 25/13 / 2 = 25/26
sin x/2 = 5/√26
sin x/2 / cos x/2 = tan x/2
cos x/2 = sin x/2 / tan x/2 = 5/√26 / -5 = -1/√26
sin x/2 = 5/√26
cos x/2 = -1/√26
tan x/2 = -5
Let X be the score on an english test which is normally distributed with mean of 31.5 and standard deviation of 7.3
μ = 31.5 and σ =7.3
Here we have to find score that separates the top 59% from the bottom 41%
So basically we have to find here x value such that area above it is 59% and below it is 49%
This is same as finding z score such that probability below z score is 0.49 and above probability is 0.59
P(Z < z) = 0.49
Using excel function to find the z score for probability 0.49 we get
z = NORM.S.INV(0.49)
z = -0.025
It means for z score -0.025 area below it is 41% and above it is 59%
Now we will convert this z score into x value using given mean and standard deviation
x = (z* standard deviation) + mean
x = (-0.025 * 7.3) + 31.5
x = 31.6825 ~ 31.68
The score that separates the top 59% from the bottom 41% is 31.68
