I'm asking this again because some mean person took the points without actually answering the question.
what is a real-life situation for equivalent expressions?

9 cows + 15 horses =24 animals in all

Step-by-step explanation:

Variables in Mathematical Expressions. In algebra, we begin to see variables, or letters that are used to represent numbers. An example of a mathematical expression with a variable is 2x + 3. All variables must have a coefficient, a number that is multiplied by the variable.

8 apples are left.

step-by-step explanation:

10-2=8

10 apples

take 2

now u have 8

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."