Question

A line passes through the points (–5, 2) and (10, –1). Which is the equation of the line?

Answer 1

The answer is A) y = -1/5x + 1

In order to find this you must first find the slope of the line. To do so, use the slope formula below.

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

In which the slope is m, the first point would be (x1, y1) and the second point would be (x2, y2). So we take the known information and we plug it in.

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

m = (-1 - 2)/(10 - -5)

m = -3/15

m = -1/5

Now that we have this, we can use the slope and either point to find the y-intercept (b).

y = mx + b

-1 = -1/5(10) + b

-1 = -2 + b

1 = b

Now that we have the slope and intercept, use both to write the equation.

y = -1/5x + 1