2x+15+x+20+30+25=180
3x+90=180
x=90/3
x=30
New angles
75,50,55
The smallest angle is 50
To solve x, you would distribute the 3 to the numbers in the parenthesis. 3x-3=5+x Now you would combine like-terms which would give you: 2x=2. Now you would divide by 2 on both sides to give you x=1. I hope you understand what I did. Hope I helped you!
A) The mean would be 1.842 and the standard deviation would be 1.339.
b) It would not be unusually low.
Explanationa) This can be modeled as a binomial distribution, since there are two outcomes (7 or not 7), the events are independent (getting a 7 on one spin does not influence the chance of a 7 on the next spin) and there are a fixed number of trials (70). In a binomial distribution, the mean is given by n*p, where n is the number of trials and p is the probability.
μ=n*p=70*(1/38) = 1.842.
The standard deviation of a binomial distribution is given by
σ=√(n*p*(1-p))=√(70(1/38)(37/38)=1.339.
b) To determine if this is unusually low, we find the probability:

Since this is not below 0.05, we do not consider this unusual.
Use the cosine rule.
c=AB=7
b=AC=8
a=BC=3
a^2=b^2+c^2-2bc(cos(A))
=>
cos(A)=(b^2+c^2-a^2)/(2bc)
=(7^2+8^2-3^2)/(2*7*8)
=13/14
=0.9286