# How do you write an equation in point-slope form for the given (-2,-1) and (3,-4)?

Jul 17, 2015

Write equation of a line
Answer $y = - \frac{3 x}{5} - \frac{11}{5}$

#### Explanation:

Slope-intercept form: y = ax + b. Find a and b.
Write that this line passing at point (-2, -1)
- 1 = - 2a + b (1)
Write that this line passing at point (3, -4)
-4 = 3a + b (2)
(1) gives -> b = 2a - 1. Replace this into equation (2):
-4 = 3a + (2a - 1) --> 5a = - 4 + 1 = - 3 --> $a = - \frac{3}{5}$
$b = 2 a - 1 = - \frac{6}{5} - 1 = - \frac{11}{5}$

$y = - \frac{3 x}{5} - \frac{11}{5}$