Substitute the numbers for letter a and b in the equation
To simplify 4/(2+7i), we multiply it by a fraction equal to one that removes the i value in the denominator. The best value to do this is the complex conjugate divided by itself, so we have 4(2-7i)/((2+7i)(2-7i)). Simplifying, we have (8-28i)/(4-(-49))=(8-28i)/53, which is a completely simplified fraction since 8 and 53 are relatively prime (or coprime), and there are no radicals in the denominator.
Answer:
Therefore the probability that a pen from the first box and a crayon from the second box are selected is 
Step-by-step explanation:
Probability:
The ratio of the number of favorable outcomes to the number all possible outcomes of the event.

Given that,
Three plain pencils and 5 pens are contained by the first box.
Total number of pens and pencils is =(3+5)=8
The probability that a pen is selected from the first box is
=P(A)


A second box contains three colored pencils and three crayons.
Total number of pencils and crayons is =(3+3)=6
The probability that a crayon is selected from the second box is
=P(B)


Since both events are mutually independent.
The required probability is multiple of the events
Therefore the required probability is


49a. r=9 & r=3
49b. r=59048 & r=19683
49c. The first equation subtracts 1 from 3^n while the second equation subtracts 1 from the value of n.
49d. ***I forgot what an exponential function is, sorry...***
CANT FIGURE OUT 50. Hope I helped...
Given:
Cylinder: height = 16 cm ; radius = 5 cm
cone: height = 12 cm ; radius = 4 cm
Volume of cylinder = 3.14 * (5cm)² * 16cm = 1,256 cm³
Volume of cone = 3.14 * (4cm)² * 12cm/3 = 200.96 cm³
Volume of air space = 1256 cm³ - 200.96 cm³ = 1,055.04 cm³