How do you write the point slope form of the equation given (12,5) and m=-3?

2 Answers
Mar 20, 2017

#y-5=-3(x-12)#

Explanation:

The point-slope form of the equation of the line is usually written in formula form as #y-y_1=m(x-x_1)#

To find a specific line, replace the m with the value for the slope, here m = -3, and the coordinates of the point using the given coordinates, #(x_1,y_1)=(12,5)#.

Usually the brackets are removed and the equation rearranged.

#y=-3x+41#

Explanation:

The slope form is:
#y=mx+b#
#m# is already given:
#y=(-3)x+b#
Since you know one solution to the equation, you can put those #x# and #y# values into the equation to solve for #b#:
#(5)=-3(12)+b#
Multiply #12# and #-3#:
#5=-36+b#
Add #36# to both sides:
#36+5=b#
#41=b#
Substitute #b# into the slope formula and you're done:
#y=-3x+41#