If you minus 3 from 108 u get 105 then divide 105 by 15 and u get 7 that ur answer because 15x7+3=108
19. 5x - 5 = 3x -9
2x = -4
x = -2
19. Answer is A
The mistake was is he subtracted at the end instead of dividing, the answer is 5/7
For a) simply substitute the speed of the car into the equation to get the braking distance.
For b) rearrange the equation to solve for x by substituting the braking distance in.
Rearranged, the equation looks like this: x = √(9d)
For c) use a calculator to find the precise value of x in question b.