Can someone make my day and me solve number 3?

X = cost of car before tax

Total cost = (cost of car before tax) + (tax amount)
Total cost = x + 5% of x
Total cost = x + 0.05x
Total cost = 1.05x

The total cost is given to be $14,512, which means 

Total cost = 1.05x = 14512

1.05x = 14512
1.05x/1.05 = 14512/1.05
x = 13,820.95238
x = 13,820.95

The total cost of the car before tax, to the nearest cent, is $13,820.95