How do you write the equation of the line that passes through the points (3, 6) and (5, 18) using function notation?

2 Answers
Jim G.
Aug 8, 2018

#f(x)=6x-12#

Explanation:

#"the equation of a line in "color(blue)"slope-intercept form"# is.

#•color(white)(x)y=mx+c#

#"where m is the slope and c the y-intercept"#

#"calculate m using the "color(blue)"gradient formula"#

#•color(white)(x)m=(y_2-y_1)/(x_2-x_1)#

#"let "(x_1,y_1)=(3,6)" and "(x_2,y_2)=(5,18)#

#m=(18-6)/(5-3)=12/2=6#

#y=6x+clarrcolor(blue)"is the partial equation"#

#"to find c substitute either of the 2 given points into"#
#"the partial equation"#

#"using "(3,6)" then"#

#6=18+crArrc=6-18=-12#

#y=6x-12" or "f(x)=6x-12#

Cem Sentin
Aug 8, 2018

#y=6x-12#

Explanation:

After using formula equation of line passes through 2 points,

#(y-6)/(x-3)=(18-6)/(5-3)#

#(y-6)/(x-3=6#

#y-6=6*(x-3)#

#y-6=6x-18#

#y=6x-12#

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