How do you find the equation of a line with m=-4 and (3,0)?

1 Answer
Mar 30, 2018

Answer:

#y = -4x + 12#

Explanation:

One way to write the equation of a line is in the slope-intercept form written like this:
#y = mx + b#
#"m=slope"#
#"b=y-intercept"# (where the line crosses the #"y-axis"#)

The problem has already given
#m = -4#
#x = 3#
#y = 0#

Normally, the equation of a line is left with #x# and #y# being variables, and #m# and #b# having values . Since we do not have a value for #b#, we will plug all those numbers in and solve.

Substituting those in, the equation should look like this.

#0 = (-4)(3) + b#

#0 = -12 + b#

#12 = b#

So the equation of the line would be:
#y = -4x + 12# graph{y = -4x + 12 [-17.13, 18.9, -2.64, 15.38]}
And this is your equation graphed. Notice how the line crosses the #"y-axis"# at #12#, and that the slope is #-4#, just like the equation says.