Question 233716
m = -4 means slope = -4.


slope-intercept form of equation of a straight line is y = mx + b.


m is the slope.


b is the y-intercept.


your equation starts of with the slope-intercept generic form of y = mx + b


replace m with -4 to get y = -4x + b


your line goes through the point (x,y) = (1,-4)


that means the x-coordinate is 1 and the y coordinate is -4.


to find the y-intercept, you replace y with -4 and x with 1 in the equation and solve for b.


your equation of y = -4x + b becomes:


-4 = (-4 * 1) + b


This becomes:


-4 = -4 + b


add 4 to both sides of this equation to get:


b = 0


Your equation that was:


y = -4x + b becomes:


y = -4x + 0 which becomes:


y = -4x


Looks like you got it right.


A graph of your equation look like:


{{{graph (400,400,-5,5,-5,5,-4x)}}}


It's got a slope of -4 and it passes through the point (x,y) = (1,-4)


when x = 1, y = -4x means that y = -4 * 1 which means that y = -4


the graph confirms that.