Y=$175+x I think this is it? one half of 175 is 87.5 so you know.
130 divided by 2.5 or 130/2.5
Answer- 52 mph
That'd be y = 70* (1-.00043)^t, where the rate of decrease is really 0.43% and t denotes the # of weeks.
This simplifies to y = 70*(0.00057)^t.
If the question is 6x-30, then the answer is 6(x-5)
Have a great day ^_^