Answer:
(4+7i)-2i(2+3i) = 10+3i
Step-by-step explanation:
We need to find the expression that is equivalent to the complex number 10+3i.
Option 1. 2i(4-5i)+(1-7i)
=8i-10i²+1-7i
∵ i² = -1
=8i-10(-1)+1-7i
=8i+10+1-7i
=11+i (incorrect)
Option 2. (4+7i)-2i(2+3i)
=4+7i-4i-6i²
=4+7i-4i-6(-1)
=4+7i-4i+6
=10+3i (Correct)
Option 3. (-3+5i)-3i(4+5i)
= (-3+5i)-12i-15i²
= -3+5i-12i-15(-1)
= -3+5i-12i+15
=12-7i (incorrect)
Option 4. 3i(4+7i)+(11+2i)
= 12i+21i²+11+2i
=12i+21(-1)+11+2i
= 12i-21+11+2i
=14i-10 (incorrect)
Hence, the correct option is (B).
We are looking for the probability :

Transform the law to standard normal like this:

The above formula is equivalent to this one:

From normal law table, we read the value of

.

Solving the above equation for the score n:


, it is the score we are looking for.
6x15= 90
9x20= 180
180+90= 270
270 - 25 = 245 dane has 245 stamps left
Answer:
Question 13: For age groups y=1 and y=1.3 response is 8 microseconds.
Question 14: The club was making a loss between 11.28 and 4.88 years.
Step-by-step explanation:
Question 13:
The age group y for which the response rate R is 8 microseconds is given by the solution of the equation

We graph this equation and find the solutions to be

Since only positive solutions for y are valid in the real world we take only those.
Thus only for age groups y=1 and y=1.3 the response is 8 microseconds.
Question 14:
The footbal club is making a loss when 
Or

We graph this inequality and find the solutions to be
and 
Since in the real world only positive values for t are valid, we take the the second solution to be true.
Thus the club was making a loss in years 