The modulus of complex number can be computed with this equation:
|z|=sqrt(Re(z)^2+Im(z)^2)
z = -2-6i
Re(z)=-2, so Re(z)^2=4
Im(z)=-6, so Im(z)^2=36
|z|=sqrt(36+4)=sqrt(40)=6.3
A factor of 30 is chosen at random. What is the probability, as a decimal, that it is a 2-digit number?
The positive whole-number factors of 30 are:
1, 2, 3, 5, 6, 10, 15 and 30.
So, there are 8 of them. Of these, 3 have two digits. Writing each factor on a slip of paper, then putting the slips into a hat, and finally choosing one without looking, get that
P(factor of 30 chosen is a 2-digit number) = number of two-digit factors ÷ number of factors
=38=3×.125=.375
d = distance between the two cities
v₁ = average speed while going from chicago to kansas city = 440 knots
t₁ = time taken to travel distance going from chicago to kansas city
time taken to travel distance going from chicago to kansas city is given as
t₁ = d/v₁
t₁ = d/440 eq-1
v₂ = average speed while going from kansas city to chicago = 110 knots
t₂ = time taken to travel distance going from kansas city to chicago
time taken to travel distance going from kansas city to chicago is given as
t₂ = d/v₂
t₂ = d/110 eq-2
Given that :
t₂ = t₁ + 3
using eq-1 and eq-2
(d/110) = (d/440) + 3
d = 440
C
work:
75 is equal to 2x+15
75-15 = 60
60/2 = 30
x=30
Answer:
case a) 
----> open up
case b) 
----> open down
case c) 
----> open left
case d) 
----> open right
Step-by-step explanation:
we know that
1) The general equation of a vertical parabola is equal to
where
a is a coefficient
(h,k) is the vertex
If a>0 ----> the parabola open upward and the vertex is a minimum
If a<0 ----> the parabola open downward and the vertex is a maximum
2) The general equation of a horizontal parabola is equal to
where
a is a coefficient
(h,k) is the vertex
If a>0 ----> the parabola open to the right
If a<0 ----> the parabola open to the left
Verify each case
case a) we have
so
so
therefore
The parabola open up
case b) we have
so
therefore
The parabola open down
case c) we have
so
therefore
The parabola open to the left
case d) we have
so
therefore
The parabola open to the right
