Question

What is the equation of the line passing through the point (2,-1) with a slope of -3

Answer 1

Note: this answer assumes that the equation of the line must be in slope-intercept form.

Answer:

`y= -3x + 5`

Step-by-step explanation:

When you need to write an equation and know its slope and a point it intersects, you can use the point slope formula
`y-y_1 = m (x-x_1)` first. In order to write an equation using this formula, the
`m`,
`x_1`, and
`y_1` must be substituted in for real values.

The
`m` represents the slope, so write the slope of this equation, -3, in its place. The
`x_1` and
`y_1` represent the x and y values of a point the line intersects. We know that the line must intersect the point (2, -1). Write 2 in the place of

`y-(-1) = -3(x-(2))`

`y+1 = -3(x-2)`

Now, to put it in slope-intercept or
`y = mx + b` form, just expand the right side and isolate
`y`:

`y+1 = -3(x-2)\\y + 1 = -3x + 6 \\y = -3x + 5`

Therefore,
`y= -3x + 5` is the answer.