Answer:
Step-by-step explanation:
(x+3)² -5 =0 , use the formula (a+b) ² = a²+b²+2ab
x²+9 +6x -5 =0 , combine like terms
x²+6x +4 =0, use the quadratic formula x = (-b±√b²-4ac)/2a
x= (-6 ±√6²-4*1*4)/2*1
x= (-6 ± √36-16) /2
x= (-6±√20)/2
x=(-6 +2√5)/2 and x=( -6-2√5) /2, factor 2 in the numerator and simplify
x= -3 +√5 and x= -3 -√5
Answer:
x=63
Step-by-step explanation:
55+62+x=180
117+x=180
180-117=63
x=63
Answer:
See below
Step-by-step explanation:
The values in the table change by $3.80 from one line to the next. Since each change from line to line changes in number of photos by 20, the average cost per photo is $3.80/20 = $0.19. There is apparently a $5.80 -3.80 = $2.00 shipping charge for numbers of photos in the range shown in the table.
Thus, the piecewise function has 3 pieces:
for x < 100: $2.00 + 0.19x
for x < 200: $4.50 + 0.17x
for x ≥ 200: $0.15x
This could be written as ...

Answer:
0.64
Step-by-step explanation:
For any distribution, the sum of the probabilities of all possible outcomes must be 1. In this case, we have to have

We're told that
, and we're given other probabilities, so we have

The expected number of calls would be
![E[X]=\displaystyle\sum_xx\,P(X=x)](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Csum_xx%5C%2CP%28X%3Dx%29)
![E[X]=0\,P(X=0)+1\,P(X=1)+\cdots+4\,P(X=4)](https://tex.z-dn.net/?f=E%5BX%5D%3D0%5C%2CP%28X%3D0%29%2B1%5C%2CP%28X%3D1%29%2B%5Ccdots%2B4%5C%2CP%28X%3D4%29)
![E[X]=1.4](https://tex.z-dn.net/?f=E%5BX%5D%3D1.4)