Question

What is the equation of the line that passes through (-3, -1) and has a slope of 2/5? Put your answer in slope-intercept form.

Answer 1

Hi there!

The general formula of A line in slope-intercept form is the following:
$y = mx + n$

In this formula m represents the slope of the line. Therefore, we can conclude that m = 2/5.
$y = \frac{2}{5} x + n$

We also know that the line passes through the point (-3, -1) and we can therefore substitute this coordinate into the formula of the line.
x = -3 and y = -1

$- 1 = \frac{2}{5} \times - 3 + n$

Multiply first.
$- 1 = - 1\frac{1}{5} + n$

And finally add 1 1/5 to both sides of the equation.
$\frac{1}{5} = n$

We can now switch sides.
$n = \frac{1}{5}$

Now we've found our value of n, which we can substitute into the formula of our line. Hence, in slope-intercept form, we find the following:
$y = \frac{2}{5} x + \frac{1}{5}$