Rates & Change
A tank has 9 gallons of water. After 3 minutes, it has 6 gallons. What is the rate of change?
-1 gallon per minute
-7 + 12
5
x - 9= -4
x=5
A climber descends 40 feet from where they were. Write an expression
x-40
If your bank account shows -$25, what does it mean?
You owe $25
The temperature drops from 50 degrees to 26 degrees in 6 hours. What is the hourly temperature change?
-4 degrees per hour
(-3)(-8)
24
-6x=42
x= -7
A temperature rises from -10 degrees to 20 degrees. Write an equation to show the total change
-10 + x = 20
Old balance: 200
Transaction: -75
New balance: ?
125
A stock loses $0.40 per week. Write an equation for the total change after x weeks.
y= -0.40x
if x= -1/4 and y= -8 , what is xy?
2
-8 + m = -20
m = -12
Andre had $500 and now has $455. Write an equation to show the withdrawal.
50 - x = 455
Old balance: -10
Transaction: -20
New balance: ?
-30
Water decreases from 12 gallons to 3 gallons in 9 minutes. How many more minutes until empty?
3 more minutes
Which expression is negative if x= -1/2 and y= -4
A. x+y
B. x-y
C. xy
D. x / y
A
0.5x= -3
x= -6
A diver descends 3/4 meters per minute. Write an equation for d minutes.
y= -3/4d
Old balance: 350
New balance: 400
Transaction: ?
+50
A tank holds 15 gallons when full. It is draining at -2 gallons per minute. When you arrive, it has 5 gallons. How many minutes BEFORE you arrived was it full?
5 minutes before
Evaluate -3/5 + 1/2
-1/10
12 - b =18
b= -6
Write an equation showing a value decreasing 2.5 units per hour from 30.
y= 30 - 2.5h
Name 2 things that -10, -20, and -30 could represent in a bank account
a transaction or money owed/debt