Question

What is the standard form equation of the line passing through (5, -3) with a slope of -3?

a.3x + y = 12
b.3x + y = -12
c.3x - y = 12
d.3x - y = -12

Answer 1

Please show your work.

Point-Slope Form is this: (y-k) = m(x-h)

We have a point: (5,-3), thus (y+3) = m(x-5)
We have the slope: -3, thus (y+3) = -3(x-5)

Now, for standard form:

y + 3 = -3(x-5)

Expand parentheses

y + 3 = -3x + 15

Add 3x to get variables on the left.

3x + y + 3 = 15

Subtract 3 to get constants on the right.

3x + y = 12 -- I think we're done!

Just one step at a time. No need to make the whole trip at the beginning!