How do i add subtractact polynomials?

Find the slope of the line y =8/9x + 1.

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9