Answer:
b. 
f. 17 hours
Step-by-step explanation:
Charges for coming to my house = $68 (this will be the constant of the equation)
Amount charged per hour labor = $17
hours = h
Total amount paid to Mike = 357
The equation that represents this situation can be expressed as:

Solve for h
(subtraction property of equality)

(division property of equality)

Mike was in my house for 17 hours.
29.75/8.5=x/4.5
using the "butterfly method"
8.5x=133.875
/8.5 /8.5
x=15.75
You have to make a proportion
<span>Let x be Joanna's heart rate immediately after running one mile.
After this heart rate x decreased by 2 over 5, Joanna's heart rate was 60 beats per minute. We can set up an equation to solve this question.
x - (2/5) x = 60
(3/5) x = 60
x = (5/3) 60
x = 300 / 3
x = 100
Joanna's heart rate immediately after running one mile was 100 beats per minute.</span>
For this case we have the following system of two equations with two unknowns:

Adding both equations we have to eliminate the variable "x":

Adding common terms, keeping in mind that different signs are subtracted and the sign of the major is placed:

Answer:

Option A