I think the problem is
2X+20=400
You just have to answer I think X and X equals that two numbers I’m not 100% sure but I’m trying to help
Answer:

Step-by-step explanation:
c varies jointly with d and the square of g


where, k is constant of proportionality.
Put the given value c = 30 when d = 15 and g = 2 and find out k


If c = 6 and g = 8 then d = ?



Hence, The value of d is 
Answer:
23 inches
Step-by-step explanation:
assuming that the desktop screen is a rectangle, then it's diagonal will form two right triangles.
by the Pythagorean theorem

then

The correct answer is 7,500.
When it's by the magnetic poles