Question

what is the equation of the horizontal line through (1,9)

Answer 1

Answer:

y-9 = 0   ( or )  y= 9 is the correct equation.

Step-by-step explanation:

equation of a line passing through a point can be given as:

$y-y_{1} = m ( x-x_{1} )$   --------------------------------------- ( 1 )

where m = slope of the line passing through  $(x_{1} ,y_{1})$.

for horizontal lines slope = 0   ( i.e.)   m = 0

and given that  $(x_{1} ,y_{1})$. = ( 1,9 )

now equation  ( 1 ) becomes

$y-9 = 0$

thus you got the answer.

Hope it helps !