Start with

Add 2x to both sides:

Subtract 21 from both sides:

Divide both sides by 5. Since it is positive, we don't have to change the inequality sign:

So, the answer is 
Answer:
The surface area is multiplied by 3.
Step-by-step explanation:
If r is the radius of a sphere its surface area = 4(pi)r^2. If the radius is doubled then its surface area = 4(pi)(2r)^2 = 4*4(pi)r^2. So the surface area becomes 4-fold or the increase in surface area is 300%.
0.00000004 to the power of 4
Your answer would be <u>0</u>
Area of a triangle is 0.5(base x height)
Base = 320mi
Height= 270+210= 480mi
0.5(480 x 320) = 76,800 miles squared