Let f(x) represents the heart beat of the person.
Now, we have been given that person’s theoretical maximum heart rate is given by 220 - x.
Also, we have been given that person strive for a heart rate that is at least 50% of the maximum. At least means greater than equal to.
Thus, we have

Also, we have been given that person strive for a heart rate that is at most 75% of the maximum. At most means less than equal to.
Therefore, the system of inequality is given by

Answer:
yes each input (time in hours) has a unique output(cost)
Step-by-step explanation:
I did the test
Answer:
x+1
Step-by-step explanation:
the answer is z-m=z+bx so z-m-z=bx and x=-mb
So it's the first option
the solution is x= - mb