I need to know the Equation used to solve part a in form of y=?x+? what goes in the blanks?

I need to know the Equation used to solve part a in form of y=?x+?

what goes in the blanks?

to know why After you answer that simple part would b good.

Then I need to know part b.

if you could explain both that would b great thaanks trying to learn this boring stuff