You can start with the form
∆y(x -x1) -∆x(y -y1) = 0
Here, we have
∆y = 11-(-3) = 14
∆x = -3-1 = -4
and we can choose (x1, y1) = (1, -3). This gives
14(x -1) -(-4)(y -(-3)) = 0
14x +4y -2 = 0
All these terms have a common factor of 2 that we can remove. Adding 1 to the result puts it in standard form:
7x +2y = 1
Use the distributive property to get 8x+28+6x+21 then combine 8x and 6x and also combine 28 and 21 to get 14x+49, do u need to go further or?
240÷15=16 seats at each table
Since there were 15 tables and 240 in total you have to divide to find the number of seats at a table