How do you write the equation of the line that passes through (-3, 3) and (2,-7)?

1 Answer
Aug 4, 2017

y=-2x-3

Explanation:

The gradient/intercept form of a linear equation is:

y=mx+c

We need to solve for the two unknowns m and c to find the equation.

First, solve for the gradient, m:

m=(y_2-y_1)/(x_2-x_1)=(-7-3)/(2-(-3))=-2

Substitute this value into the gradient/intercept form:

y=-2x+c

Now substitute in any point on the line to solve for c:

(-3,3):

3=-2(-3)+crArr3=6+crArrc=-3

c is the y-intercept.

Inserting c and m into the original equation gives the answer:

:.y=mx+c=-2x-3