Your answer for Part A looks good.
For Part B, you want to get it into Ax+By=C form, where A, B, and C are real numbers and more commonly they’re integers.
Step 1: Get rid of the fractions.
The common denominator from your answer to Part A is 12, so multiply everything on both sides by 12:
y = -5/12 x + 19/2 becomes
12y = -5x + 114
Step 2: get the x-term over to the left side by adding 5x to both sides
5x + 12y = 114