Use the following information

# Machine Maintenance

Month Hours (X) Costs (Y)

Jan 3,000 $440

Feb 4,500 $690

Mar 8,000 $510

Apr 7,000 $600

May 6,000 $550

Jun 9,000 $980

Jul 3,500 $840

Aug 5,500 $600

What is "a" Value in the equation of the line y = a +bx using the high-low method and this data?

Select one: a. a = 120 b. a = 170 c. a = 160 d. a = 150