# How do you write an equation of a line with slope of 3 and contains the point (4, 9)?

##### 2 Answers

Mar 22, 2018

#### Explanation:

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

#•color(white)(x)y=mx+b#

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

#"here "m=3#

#rArry=3x+blarrcolor(blue)"is the partial equation"#

#"to find b substitute "(4,9)" into the partial equation"#

#9=12+brArrb=9-12=-3#

#rArry=3x-3larrcolor(red)"is the equation of the line"#

Mar 22, 2018

#### Explanation:

You can use the equation of a line in point-slope form:

Make the following substitutions:

That will give you:

Then simplify: