Question 759451
NOTE:  You seemed to have only made a transpositional, copy mistake; and if you had not, your result would have probably worked with no difficulty... See final comments below.

d=driving speed
w=walking speed
x=?


Kind of Move______speed_________time____________distance
Driving___________105___________(___)___________(___)
Walking___________6_____________(___)___________(___)
Total____________________________7______________170


Interesting, we do not know the separate times and we do not know their corresponding distances.  They must be based on two different variables for the time portions.


Let's use d and w for each time portion:

Kind of Move______speed_________time____________distance
Driving___________105___________(d)___________(105d)
Walking___________6_____________(w)___________(6w)
Total____________________________7______________170


You have enough information to form two equations.  d is time spent driving and w is time spent walking.

{{{highlight(d+w=7)}}} and {{{highlight(105d+6w=170)}}}

You made a small symbolism mistranspose mistake and that is what stopped you from getting a sensible result.  Look at the system of equations!  Almost the same as yours;  just need "105" instead of "150".


Try the job again and you should find your answer will work!