David rowed a boat upstream for three miles and then returned to point he started from.
the entire journey took four hours.
the speed of the stream is one mile per hour.
find david's speed in still water.
david's speed in still water is ? miles per hour?

step-by-step explanation:

answers available in this download

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x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.