You need to get x by itself. Add 6 to both sides.
x = 14
Consider this option:
1. if to re-write the condition, it is given: total time t=8 hours; upstream=downstream=6 miles; V_boat=4 m/h., V_current=V=?
2. note, that total time=time_upstream+time_downstream, where time_upstream=6miles/(V_boat-V) and time_downstream=6miles/(V_boat+V). Using this it is possible to make up and solve the following equation:

answer: √10
P.S. the roots of the equation are √10 and (-√10), only positive values is needed for V.
<span>If the company, hewerrtt, would like to make letter codes using all of the letters in the word hewerrtt, they would be able to make five codes. Altogether, there are eight letters in the word, but there are duplicates of the letter e, the letter r, and the letter t, so that takes out three possibilities. Three subtracted from eight is equal to five, therefore the company can make five codes using the company name.</span>
J

j=agv where a is a constant of proportionality.
j=1 when g=4 and v=5
1=a*4*5
1=20a
a=1/20
a= 0.05
j=0.05gv
When g=10 and v=9,
j=0.05*10*9
j=0.5*9
j=4.5
An equation with more than one variable is called a "literal Equation"