(a ± b)² = a² ± 2ab + b² . . . . . . . (signs match)
The middle term is twice the product of the roots of the other two terms. This tells you the terms of the binomial are the square roots of the end terms.
The sign in the binomial will match the sign of the "2ab" term. The order of terms in the binomial doesn't matter. (a±b)² = (b±a)² when signs match.
Answer:
Step-by-step explanation:
Given that X is the number of months between successive payments
Cumulative distribution function of X is
a) PMF of x would be
b) 
Set equal to eachother
(2x+1) = 79
Subtract 1 from both sides
2x=78
Divide 2 from both sides
2x/2=78/2
X= 39
Set up and solve an equation:
3(90-x) = (180-x). Then 270 - 3x = 180 - x, or 270 - 180 = 2x.
90 = 2x, so x = 45 deg.
Is this true? 3(90-45) = (180-45)? If so, x = 45 degrees is correct.
