Move the 8 over
-x=3x-8
Move the 3x over
-x-3x=8
-4x=8
Divide by -4
x=-2
Answer:

And using the cdf we got:

Step-by-step explanation:
Previous concepts
The exponential distribution is "the probability distribution of the time between events in a Poisson process (a process in which events occur continuously and independently at a constant average rate). It is a particular case of the gamma distribution". The probability density function is given by:

And 0 for other case. Let X the random variable that represent the random variable of interest and we know that the distribution is given by:

We know the variance on this case given by :

So then the deviation is given by:

And if we solve for
we got:

The cumulative distribution function for the exponential distribution is given by:

Solution to the problem
And for this case we want to find this probability:

And using the cdf we got:

Solution :
Given :
Span of the roof = 48 feet
Length of the rafter = 30 feet (including the 4 feet overhung)
So, for the 30 feet long rafter, 26 feet will be rafter length from the high point of the roof to the edge of the roof and 4 feet will be the roof overhung.
Therefore, the horizontal span per rafter is

= 24 feet
a). So the rise of the roof is
= 10 feet
b). Pinch of the roof is 


c). The percent of the roof used as overhung is


= 13.33 %
X=0. Y=-2. There is only one x value for this question.
For <span>12/15=47/50, we multiply 12/15 by (1/3)/(1/3) to get 4/5. For 47/50, we multiply it by (1/10)/(1/10) to get the same denominator and 4/7/5. They are not equal.
For 16/36 and 12/27, we'll notice that 36 and 27 are both multiples of 9, so we need to get that as the denominator! Multiply 16/36 by (1/4)/(1/4) because 9 goes into 36 4 times and 12/27 by (1/3)/(1/3) due to that 27 goes into 9 3 times, we get 4/9=4/9 - these are equal!
I challenge you to get the rest of them on your own using my techniques!</span>