Please help me

(3x^7-5x^5+10x^3-4x^2+1) divided by (x^2-18) is

The ratio pv to nrt is plotted against pressure for ch4 at 0°c and 200°c. why does the curve for 0°c drop below the horizontal line for an ideal gas whereas the curve for 200°c does not?

What is the length of the unknown leg in the right triangle ?

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.