Question

What is the equation of the following line written in general form?

a) y - x + 1 = 0
b) x - y + 1 = 0
c) -x - y + 1 = 0

Answer 1

The correct answer is b) x - y + 1 = 0

Explanation:

In order to find this, start by finding the slope using the two points given.

m(slope) = (y2 - y1)/(x2 - x1)

m = (5 - 2)/(4 - 1)

m = 3/3

m = 1

Now that we have the slope, we can plug into point slope form along with either point. Then we can solve for 0 to see which equation is correct.

y - y1 = m(x - x1)

y - 2 = 1(x - 1)

y - 2 = x - 1

-x + y - 2 = -1

-x + y - 1 = 0

x - y + 1 = 0