Answer:
(a) The system of the equations
has no solution.
(b) The system of the equations
has many solutions 
Step-by-step explanation:
(a) To find the solutions of the following system of equations
you must:
Multiply
by 2:

Subtract the equations

0 = -3 is false, therefore the system of the equations has no solution.
(b) To find the solutions of the system
you must:
Isolate x for 

Substitute
into the second equation

The system has many solutions.
Isolate y for 

Answer:
C.
Step-by-step explanation:

Answer:
See below ↓
Step-by-step explanation:
19.
20.
Answer:
There are 3478761 ways to select the first 5 numbers
Step-by-step explanation:
As understood from the statement of this problem we assume that it does not matter the order in which the first 5 white balls are selected.
In this case it is a combination.
So, what we want to know is how many ways you can choose 5 white balls out of 55.
Then we use the formula of combinations:

Where you have n elements and choose x from them.
Then we look for:
