Solution for 5 b)
I know that
t(90 000)=a • square root of 120 000- 90 000
How do I find the thickness?

We need the value of from the first question. The initial thickness is 12mm, there "initial" means that the car has been driven for 0 kilometers. So, we know that

Now, the second questions asks for the thickness after the car has driven 90000 km. So, we simply need to plug in the equation to get

the slope of the line is 60

one point on the line is (40,10)

step-by-step explanation:

in the equation outside the parenthesis the equation always tells you the slope. in this case it is 60.

in the parenthesis is also says 40 which is x because it is near the x and 10 is y because it is near y.