When a linear equation is in the form y = mx + c, the c, or constant, is the intercept on the y axis, meaning it crosses the y axis at (0, 1).
The gradient (1/3 in this case) is how much the y increments (or decrements) per increase of 1 of the value of x.
This would mean that there would be one point at (0, 1), and another at (3, 2). Draw a line from these two points and beyond, and that is the graph sketched.
Given the two options above, in order to come up with the best plan we have to calculate the future value of money in each plan.
compound interest is given by:

Option 1
p=$500
r=2%=0.02
t=1 year

Option 2
p=$500
r=2/12=1/6
n=1*12=12
hence:

=$509.09
Comparing the two plans above, option 1 is the best.
b] Option 1 is the best because she will secure $510 as compared to option 2 which has interest rate that reduces her amount by $1 after one year due to annual charges. The total amount of money she will have at the end of the plan is $510.
If x is how much his income is then 2/5x+1/5x= 3/5x for rent and utilities. x-3/5x=2/5x leftover. 3/4×2/5x=3/10x for food. 3/5x+3/10x=9/10x spent on rent, utilities, and food and rec. He saves the rest which is x-9/10x= 1/10x so if 1/10x=193.50
x= $1,935 for his income
45/120 = 3/8
as the simplest fraction