Please help kind frustrated and confused

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?

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

Find the measure of angle y. round your answer to the nearest hundredth. ( type the numerical answer only) a right triangle is shown with one leg measuring 5 and another leg measuring 14. an angle across from the leg measuring 5 is marked y degrees. numerical answers expected!