define a variable to represent a real life quantity, such as length in centimeters or money in cents. then use the variable to write a mathematical expression to represent one of your daily activities. describe in words what your expression represents and explain your reasoning.

Well, one example could be

Velocity in m/s, km/h, etc...

You could use the equation: D=v/t
and say that it's used in daily life to calculate...

Speed, while also determining time and distance for engineering.

Another variable could be tax, which is also in money..

Ex: y = 0.15x + x
Where 0.15 is the tax % and x is the price of the product. This will tell you have much more you will have to pay on the store value.

To define a variable representing a real-life quantity, let's say we choose the variable "c" to represent the length of a side in centimeters. Now, let's use this variable to write a mathematical expression representing the time it takes to walk a certain distance.

Let's assume you walk at a steady speed of 5 centimeters per second. We can then use the equation:

time = distance / speed

In this case, the distance will be represented by "c" centimeters, and the speed will be 5 centimeters per second. So, the mathematical expression would be:

time = c / 5

This expression represents the time it takes to walk a distance, where the distance is measured in centimeters and the speed is 5 centimeters per second.

For example, let's say you want to know how long it would take to walk a distance of 20 centimeters. You can substitute "c" with 20 in the equation:

time = 20 / 5
time = 4 seconds

Therefore, the expression "c / 5" represents the time in seconds it takes to walk a distance of "c" centimeters at a speed of 5 centimeters per second.