Answer:
(A) 45x +455= 905
10 hours of labor
Explanation:
Start by defining the variable x:
Let x be the number of hours of labor.
Total bill= parts +labor
905= 455 +45x
(A) 45x +455= 905
_____
Solving for x:
45x +455= 905
Bring constants to the other side of the equation:
45x= 905 -455
45x= 450
x= 450 ÷45
x= 10
Since $45 is an hourly rate, the units of x we are looking at is hours.
Thus, 10 hours of labor is needed to complete the job.