Question

Which is an equation of the line through (0,0) and (9,-4)?

A. y = -4/9x
B. y = -9/4x
C. y = 9/4x
D. y = 4/9x

Answer 1

option A:

y = -4/9x

Explanation:

the equation of the line is, y = mx + c

the given two co-ordinates of the line are,

x1, y1 = 0, 0

x2, y2 = 9, -4

slope, m = y2 - y1 / x2 - x1

= -4 - 0 / 9 - 0 = -4/9

to find the value of constant c, let's take any (x, y) co-ordinates

i am taking x1, y1 = 0, 0

0 = -4/9(0) + c

c = 0

thus, by substituting the values the equation of the line is,

y = -4/9x + 0

y = -4/9x