Answer: 3x^2 + 7x -15
I dunno if u want me to factor it tho
Compound percentage reduction can be calculated by multiplying the initial number by (1-x)^t where x is the percentage reduction (/100, i.e. 1% reduction is 0.01), and t is the number of times it has reduced.
So:
a)

Where t is the number of weeks.
We can then just substitute in to work out the final pressure:
b) p = 45*0.94^6 =
31psi
19 divided by 40 is .475 so it’s -29.475