Answer:
a. 
Step-by-step explanation:
The given equation is;

To solve by the x-intercept method we need to graph the corresponding function using a graphing calculator or software.
The corresponding function is

The solution to
is where the graph touches the x-axis.
We can see from the graph that; the x-intercepts are;
(-1,0),(3,0) and (6,0).
Therefore the real solutions are:

To solve this you would use the pythagorean theorem since the brace is making the frame look like two right triangles. The theorem states that for a triangle with a right angle, A^2+B^2=C^2. A and B are the sides of the frame and C is the brace which is like the hypotenuse of the triangle. It doesn't matter which side is A or B so you can put 6 or 8 in place of either in the equation. 6^2+8^2=C^2. If you simplify this it equals 36+64=C^2, which then simplifies to 100=C^2. Then you take the square root of both sides (what number multiplied by itself = the number you are trying to get, in this case, 100). So then you get C=10 because 10x10=100. So the length of the diagonal brace is 10ft.
I suppose you mean to have the entire numerator under the square root?

We can use a trigonometric substitution to start:

Then for
,
; for
,
. So the integral is equivalent to

We can write

so the integral becomes

X = 30 I think as angle on straight line = 180 so 180-103 = 77 , 30+43 = 73 , 77+73 = 150 , 180-150= 30 , then opposite angles are the same so therefore x = 30 degrees