Question #b04b9

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Answer 1 · 2016-08-10T19:05:02

#y = -5x -21#

Slope intercept form means #y = mc + c# because in this form we can read off the slope (m) and the y-intercept directly.

We know the slope, but the point #(-5.4)# is not the y-intercept.
It would have to be #(0,c)#

There are 2 methods:

Method 1 .: Substitute into #y = mx +c# and find a value for #c#

#4 = (-5)(-5) + c#
#4 = 25 + c#
#-21 = c#
Substitute for #m and c#

The required form is #y = -5x -21#

Method 2: Substitute into #y-y_1 = m(x-x_1)#

#y-4 = -5(xcolor(red)(-(-5)))#

#y color(blue)(-4)= -5(xcolor(red)(+5))#
#y = -5x -25color(blue)(+4)#