Answer:
169
Step-by-step explanation:
if S(n)=n^2
so,S(13)=13^2
n=13
n^2=13^2
=169
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.
When evaluating, you must combine like terms first, so subtract 4 from 1/2 then multiply that number by -7/4, this will give you the value of x.
<h3>
The constant of proportionality is k = 5</h3>
For direct proportion equations, you divide the y value over its corresponding x value to get the value of k.
For example, the point (x,y) = (2,10) is on the diagonal line. So k = y/x = 10/2 = 5.
Another example: the point (x,y) = (6, 30) is also on the same diagonal line, so k = y/x = 30/6 = 5 is the same result as before.
You can use any point on the diagonal line as long as it is not (0,0). This is because division by zero is not allowed.
side note: the direct proportion equation y = k*x becomes y = 5*x which is the graph of that diagonal line. The slope is m = 5, the y intercept is b = 0. All direct proportion graphs go through the origin as shown in the diagram.
Answer:
C. 38cm
Step-by-step explanation:
hope this helps