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
So let's find the unit rate of these.
18 mi/ 2 hrs = 9 mi/ 1hr
45 mi / 5 hrs = 9 mi/ 1 hr
So you are running 9 miles an hour.
If you have any questions please comment! :)
15X=12X+12
Subtract 12X
3X=12
X=4
Speed of Morris is 47.95 mph
Step-by-step explanation:
- Step 1: Convert 3 feet per second to miles per hour.
⇒ 3 ft/s = 3/1.467 mph (∵ 1 mph = 1.467 ft/s)
= 2.05 mph
- Step 2: Find the speed of Morris.
Speed of Morris = 50 mph - 2.05 mph = 47.95 mph
Just finished doing the math and the correct answer should be B: 5.3 Hope this helps:)