Answer: 1) You forgot to change the sign over there. You have to subtract over there.
2) Just be careful while solving equations while changing the signs
Looks like you going to summer school
Let's say Bailey takes "b" days to paint it.
and Andrew takes "a" days to paint the same house.
now, Andrew is 6 times faster than Bailey, therefore, if Andrew takes "a" days to do it, Bailey takes then "6a" days, or b = 6a.
now, the year they worked together, they finished it in 7 days.
so, after 1 day then, they have only done 1/7 of the whole work.
and Andrew for one day, has done 1/a of the house, whilst Bailey has done 1/b of the house or 1/(6a).

Answer
I) A job pays $15/hr with no bonus first day pay.
II) A job pays $15/hr with a $20 bonus first day pay.
Step-by-step explanation:
The y-intercepts would represent additional income that is added on to the base wage. It means it is what the worker would already earn (one-time), adding on to their standard pay.
Let X represent hours, and the y-intercept be what is mentioned above.
I) 15x + 0
II) 15x + 20