Answer:
1) y = 0.3x + 1000
2) slope = 0.3
The slope is the fraction of the monthly sales that is added to your salary.
3) y-intercept = 1000
The y-intercept is the fixed part of the salary, $1000.
4) The salary is $2500
Step-by-step explanation:
1)
monthly salary = fixed part + variable part
The fixed part is $1000. Every month you receive $1000 no matter the amount of sales.
The variable part varies according to the amount of sales. You get 30% of the of the monthly sales. Let the monthly sales be x. The variable part is 0.3x
Let the monthly salary = y.
y = 1000 + 0.3x
y = 0.3x + 1000
2)
slope = 0.3
The slope is the fraction of the monthly sales that is added to your salary.
3)
y-intercept = 1000
The y-intercept is the fixed part of the salary, $1000.
4)
In this case, x = 5000
y = 0.3x + 1000
y = 0.3(5000) + 1000
y = 1500 + 1000
y = 2500
The salary is $2500.
and 
on the coordinate plane is 
