Answer:



Step-by-step explanation:
Given


maximum
minimum
Required
Solve graphically
First, we need to determine the inequalities of the system.
For number of coins, we have:
because the number of coins is not less than 20
For the worth of coins, we have:
because the worth of coins is not more than 0.80
So, we have the following equations:


Make y the subject in both cases:


Divide through by 0.01



The resulting inequalities are:


The two inequalities are plotted on the graph as shown in the attachment.
--- Blue
--- Green
Point A on the attachment are possible solutions
At A:

Answer:
x = 55
Step-by-step explanation:
To find the value of x
3x - 35 = 130 (vertically opposite angles are equal)
3x = 130 +35
3x = 165
x = 165/3
x = 55
Answer:
Decrease
Step-by-step explanation:
50 is bigger than 20, so it's decreasing and the units are the same.
Use cymath it gives you the math answers but the answer is x=74
(-6, 4), (-3, -8), and( 1, -1)