It would be 18.72$. Hope dis helps :)
-12.6 as a percent is -1260%
1. The surface that will be exposed to the rain is the lateral surface of the cylinder and the hemisphere.
2. The lateral area of the cylinder is a rectangle with height equal to the height of the cylinder and width equal to the circumference of the base of the cylinder.
3. the circumference of the base = 2

r=2*

*5=10

so the lateral area = 10

*h=10

*40=400

(

)
4. The surface area of a sphere is

so the surface of the hemisphere =

(

)
5. Total area exposed = 450
Your basically building a new equation with the two functions given to you.
(sqrt(3x + 7)) + (sqrt(3x - 7)) = 0
Then just open up the brackets and simplify further.
sqrt(3x + 7) + sqrt(3x - 7)= 0
Nothing to special really happened there, just removed the brackets. Now you move one of the radicals to the other side so you can square the whole equation.
sqrt(3x + 7) = - sqrt(3x - 7)
Then go ahead and square both sides to remove the radical.
3x + 7 = 3x - 7
Now if you kept trying to isolate x, you find that both sides will just cancel each other out and you are left with,
7 = -7
Since that statement isn't true your answer will be that there is no solution to this equation.
x ∈ Ø