Which expressions are equivalent to 6 +(-x) + 2x + (-7) + 2x

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?

Write the expression in simplified radical form. show all steps and work including any foil method work. (hint: use the conjugate. no decimal answers.) (9-2√3)/(12+√3)

Find the equation of the trend line (line of best fit). show your work i'm using the points (34,76) (42,91)