Question

What is the equation of a line that passes through the point (0, -2) and has a slope of -3? y = -3 y = -3x - 2 y = -2x - 3 y = -2

Answer 1

Since y =mx + c

the coordinates are (x,y) so we can substitute them into y =mx +c

also -3 can be written as -3/1 or 3/-1

(-2) = -3/1 (0) +c

rearranging for c

-2 = c ( since -3/1 multiplied by 0 = 0)
we can now say y = -3/1 x + (-2) which simplifies to y= -3/1 x - 2

Answer 2

The general equation of a line is y = mx +b. 
m is equal to the slope, so for this problem it is m = -3 
b is equal to the y-intercept (the y-point when x = 0) so according to this since it passes through (0, -2), x=0 at y = -2 
The equation of the line is: y = -3x - 2