The question is related to trigonometry and we have to use the formula of double angle .
Here we use double angle formula of tangent function which is

Given expression is

Comparing it with double angle formula, we will get x = 5
SO the required expression is equal to


So the answer is tan(10) .
You can use the trigonometric identity

.

The requirement that

eliminates -1/6 from being another solution.
I know for a fact that the Airjet Express had shorter flight times because it had lesser dots than the Cross Country Airlines. Hope this helped!
First we need to find the gradient of K
which is y1-y2/x1-x2
(-1,3) and (5,-2)
so it becomes 3-(-2)/-1-5
m=-5/6
when two lines are perpendicular their gradients multiply to make -1
that means the gradient of L has to be 6/5
we can substitute the point on L (5,-2) and the gradient of 6/5 into y=mx+c
-2 = (6/5) x 5 + c
c = -8
the equation of line L is y= 6x/5 -8