Answer
$\frac{\sqrt{x^2-6x+10}}{4} + \frac{\sqrt{x^2+4}}{2}$
Work Step by Step
Find the time needed to walk.
$T1=distance/speed=\sqrt{1^2+(x-3)^2}/4=\frac{\sqrt{x^2-6x+10}}{4}$
Find the time needed to row.
$T2=distance/speed=\sqrt{2^2+(x)^2}/4=\frac{\sqrt{x^2+4}}{2}$
Find the total time of the trip.
$T = T1+T2 =\frac{\sqrt{x^2-6x+10}}{4} + \frac{\sqrt{x^2+4}}{2}$
