Question

Find an equation of the line. Write the equation in standard form.
Horizontal; through (3,-9)

Answer 1

y = -9

Explanation:

Standard form of the equation of a line is ...

ax + by = c

When that line is a horizontal line, this can be reduced to ...

y = c

The value of c must be the same as the y-coordinate of the point you want this line to go through.

y = -9 . . . . . . horizontal line through (3, -9)