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:
1.2
Step-by-step explanation:
(0.85 + 0.50 + 0.15) - 0.30 Given
Simplify by adding in the parentheses first
(0.85 + 0.50 + 0.15) - 0.30
(1.35 + 0.15) - 0.30
(1.5) - 0.30
Subtraction Property
1.5 - 0.30
1.2
#2
2x - 4y = -2
2x + 3y = -16
------------------subtract
-7y = 14
y = 14/-7
y = -2
2x - 4y = -2
2x - 4(-2) = -2
2x + 8 = -2
2x = -2 -8
2x = -10
x = -10/2
x = -5
answer x = -2 and y = -5
check:
2(-5)- 4(-2) = -2
-10 +8 = -2
-2 = -2.....true
2x + 3y = -16
2(-5)+3(-2) = -16
-10 + (-6) = -16
-16 = -16...true
75% of 12 can be represented with the equation 75/100=x/12
Then to solve
75(12)= 100x
900 = 100x
9=x
So the distance from the school to the park is 9 miles.
Answer:
(1) 56 miles/hour
Step-by-step explanation:
We need to find the average rate of change from t = 2 to t = 9.
At t = 2 hours, d = 106 miles.
At t = 9 hours, d = 498 miles.
The average rate of change in function f(x) from x = a to x = b is
[f(b) - f(a)]/(b - a)
average rate of change from t = 2 to t = 9 =
(498 - 106)/(9 - 2) = 392/7 = 56
Answer: (1) 56 miles/hour