Answer:
x= 3
Step-by-step explanation:
19x-5=7+15x
19x-15x=7+5
4x=12
x=12/4
x=3
b must be equal to -6 for infinitely many solutions for system of equations
and 
<u>Solution:
</u>
Need to calculate value of b so that given system of equations have an infinite number of solutions

Let us bring the equations in same form for sake of simplicity in comparison

Now we have two equations

Let us first see what is requirement for system of equations have an infinite number of solutions
If
and
are two equation
then the given system of equation has no infinitely many solutions.
In our case,

As for infinitely many solutions 

Hence b must be equal to -6 for infinitely many solutions for system of equations
and
Answer:
For c=5 there are not solutions for the compound inequality
Step-by-step explanation:
we know that
In the compound inequality
-----> inequality A
-----> inequality B
The solution of the system of inequalities must satisfy inequality A and must satisfy inequality B
so
If c=5
then
There is no solution that satisfies both inequalities simultaneously.
therefore
For c=5 there are not solutions for the compound inequality
the answer would be 67,127 because the number in the ones would be 7 and the tens number would be 2 since it wouldn't more than 1.
67,102
67,135
1-7
67,127