I think the answer is Garry has to invest 2,035 dollars a month for 30 years to reach his goal of 750,000 dollars
Um.. Both of those equations are the exact same. Divide both sides of the first equation by 6. You get:

That is the exact same as the second equation. This system has an infinite number of solutions. 5x - 7y = -1 is a line, so basically every point on that line is a solution to the system.
For example,

and

would work, but so would

and
No. In order to be proportional, y must change directly with x.
Looking at the first two pieces of data, let's find the ratio between x and y.
2/5 and 3/6. These should be equivalent of the table is proportional.
Answer:
Every number of years 365 and I have been trying to get a hold of