1. Find the equation of the line with slope -2 and passing through (-1,-5)

There is a graphing equation that is very useful; it's called the "point-clope" form.

Obviously, you'll need both a point and the slope to use it.

It is:    y - y1  =  m( x - x1)

where  m is the slope and the known point is (x1, y1).

1)  m = -2        (x1, y1)  =  (-1, -5)  --->  x1 = -1  and  y1 = -5

     Placing those into the formula:  y - -5  =  -2(x - -1)

     Simplifying:  y + 5  =  -2(x + 1)    --->    y + 5  =  -2x - 2    --->    y  =  -2x - 7

2)  This formula needs the slope, so find the slope using    m  =  (y2 - y1) / (x2 - x1)

     (2, -3)  --->  x1 = 2  and  y1 = -3         (6, 5)  --->  x2 = 6  and  y2 = 5

     m  =  (5 - -3) / (6 - 2)    --->    m = 8 / 4    --->    m = 2

     Using the point-slope formula:    y - -3 = 2(x - 2)    --->    y + 3  =  2x - 4    --->    y  =  2x - 7