Question

Can anybody tell me why it’s “-275”? Why is it negative ? And what is the formula for finding y? And if y=b how do you find b?

Answer 1

Answer:

275 is the amount SPENT per month for rent. Since you are decreasing that amount from your savings, it is represented with a negative sign.

The formula is: y = mx + b      where

• m is the rate             -->   -275 per month
• b is the fixed rate     --> 3500 savings

If you think about it logically - You have 3500 and spend $275 per month

1st month: 3500 - 275 = 3225

2nd month: 3225 - 275 = 2950

3rd month: 2950 - 275 = 2675

4th month: 2675 - 275 = 2400

5th month: 2400 - 275 = 2125

6th month: 2125 - 275 = 1850

It is easier to write it as an equation where x is the number of months and y is the balance for that month.

y = -275x + 3500

To check if the point (6, 1850) is on the line, input x = 6 and y = 1850

     y = -275x   +  3500

1850 = -275(6) + 3500

1850 =  -1650  + 3500

1850 =        1850

Since it makes a true statement, (6, 1850) is a point on the line.