Answer
(a) $y=0.434x+15$
(b) See the image below.
(c)The slope represents rate of change of pressure with respect to depth $xft$.
$y$-intercept represents pressure at the surface of the ocean.
(d) $\approx195.85ft$
Work Step by Step
(a) We can find the equation using slope notation (let $y$ be the pressure and $x$ feet below the surface) :
$m=\frac{y-y_0}{x-x_0}=\frac{y-15}{x-0}$
$m=\frac{y-15}{x}$
$y=mx+15$
Slope $m$ is $4.34$ for every $10ft$ and $0.434$ for every $ft$.
$y=0.434x+15$
(b) We can graph the linear equation using a graphing calculator. See the image above.
Or simply input any value in the equation to find at least $2$ points and connect these points.
(c) The slope represents rate of change of pressure with respect to depth $xft$.
$y$-intercept represents pressure at the surface of the ocean.
(d) $y=100$
$100=0.434x+15$
$0.434x=85$
$x\approx 195.85ft$
