It takes a boat 4 h to travel 75 km downstream. let x represent the boat’s speed in still water, and let y represent the water’s current in kilometers per hour.
the water is moving at 3.5 kmph. what is the speed of the boat?
kmph

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116