Find the equation of a line that passes through (-2, 5) and (-4, -5).

Answer 1

To find the equation of a line (y=mx + b), that passes through 2 points, here is the process:

1. Calculate Slope: (y₂ - y₁)/(x₂ - x₁) = (-5-5)/(-4--2) (note the double negative, making it a positive); so slope (m) = -10/-2 = 5
2. Put m into the equation: y = 5(x) +b
3. Now use either set of points to substitute in for x and y and solve for b: -5 = 5(-4) + b, solve for b giving you -5 = -20 + b, so b=15
4. Plug b into the equation from #2 above gives you the equation of the line: y = 5x + 15