Question 85190
a)Equation of a line with slope 'm' and through (x1,y1) is given by

              y-y1 = m(x-x1)

==>          y -(-3) = (-2)(x-1)
==>          y + 3 = -2x + 2
==>          y = -2x + 2 - 3
==>          y = -2x - 1 is the required equation.

b)  Slope = 0 and passes through (2,-1)

==>          y - (-1) = 0(x-2)
==>          y + 1 = 0
==>          y = -1 is the required equation.

c)  Slope = undefined and passes through (-1,2)

==>          y - 2 = (1/0)(x-(-1))[undefined = 1/0]

==>         0(y-2) = 1(x+1)
==>           0 = x + 1
==>           x = -1 is the required equation.

{{{ graph( 300, 200, -6, 5, -10, 10, -2x-1,-1) }}} 


In the above graph, the red line represents (a) and green line represents (b).(c) is not shown on the graph, but it is a line parallel to y axis and through x = -1(left of y axis)


Good Luck!!!