Boat speed callie took 20 min to drive her boat upstream to water-ski at he
ite spot. coming back later in the day, at the same boat speed, took her 15 min.
the curent in that part of the river is 5 km per hr, what was her boat speed?

1. use commutative property to reorder the terms.2x+81=0.2. move the constant to right side by adding its opposite on both sides. 2x+81-81=0-81.2x=(-81).3. divide the equation on both sides.2x ÷ 2 = 81 ÷ 2.x = -81/2. your answer is -81/2. if you need to simplify it into a decimal, it’s -40.5.

90

  example you can find the perimeter by addig all of its respective sides as such: (12+x)+(12+x)+(7+y)+(7+y).  adding like terms will result in   2x+2y+38    if you chose  xy+7x+12y+84, you multiplied the two sides to find the area.  if you chose  x+y+19