The slope (m) of the line graphed is -4/2, because the line goes down 4 (-4) and over 2 (+2), which is change in y over change in x
m = -4/2 = -2
the y-intercept (b) of the line = -1, because the line crosses the vertical line at x=0 at y=-1
now for the equation:
y = mx + b
y = -2x + -1 = -2x - 1
f(x) = -2x-1
the last answer is correct
8% lower means the gauge is showing 92% of the original pressure
( 100% - 8% = 92%)
Divide the pressure the gauge is showing by 92%
33.58 / 0.92 = 36.5
The actual pressure is 36.5