Answer: The mechanics spent about 8.5 hours working on the car
Step-by-step explanation: The total bill was $637, a portion of that being getting the parts which was $280. 637-280=357
357/42=8.5
Solve for R:
R + 3 = -(1/2 + 6)
Put 1/2 + 6 over the common denominator 2. 1/2 + 6 = (2×6)/2 + 1/2:
R + 3 = -(2×6)/2 + 1/2
2×6 = 12:
R + 3 = -(12/2 + 1/2)
12/2 + 1/2 = (12 + 1)/2:
R + 3 = -(12 + 1)/2
12 + 1 = 13:
R + 3 = -13/2
Subtract 3 from both sides:
R + (3 - 3) = -13/2 - 3
3 - 3 = 0:
R = -13/2 - 3
Put -13/2 - 3 over the common denominator 2. -13/2 - 3 = (-13)/2 + (2 (-3))/2:
R = (-13)/2 - (3×2)/2
2 (-3) = -6:
R = (-6)/2 - 13/2
(-13)/2 - 6/2 = (-13 - 6)/2:
R = (-13 - 6)/2
-13 - 6 = -19:
Answer: R = (-19)/2
