Question

An equation of the line that contains the origin and the point (1, 2) is A. y = 2x B. 2y = x C. y = x -1 D. y = 2x +1 E. y/2 = x - 1

Answer 1

A

Explanation:

the equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

calculate m using the slope formula

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

let (x₁, y₁ ) = origin (0, 0 ) and (x₂, y₂ ) = (1, 2 )

substitute these values into the formula for m

m =
`(2-0)/(1-0)` =
`(2)/(1)` = 2

since the line passes through the origin , the y- intercept c = 0

y = 2x ← equation of line