Answer:
gradient = slope = [tex]\frac{y_{2} -y_{1} }{x_{2} -x_{1} }[/tex] = [tex]\frac{rise}{run}[/tex]
Slope intercept Form equation : y = mx + b
m = slope or gradient
b = y - intercept ( where the line crosses the y = axis)
x and y = are place holders for a coordinate pair that makes the equation true
c) y = -6x + 8
The -6 is the m. It's the slope or gradient.
the + 8 is the b. It's the y- intercept.
d) y = 4
This is a horizontal line. It intercepts the y-axis at 4.
That means the 4 is the y-intercept.
There is no x. That means the slope is 0. The line rises 0 as it runs left to right.
e) y -4x= 0
equation needs to be is standard form y = mx + b.
add 4x to both sides in order to isolate the y variable.
y = 4x + 0.
The slope or gradient is 4. The y - intercept is 0. The line crosses through the origin.
f) y -x = -8
Add x to both sides.
y = x - 8
There is one x. That means the gradient is 1. The y-intercept is the -8
g) y + 3x = 7
Subtract 3x from both sides.
y = -3x + 7
-3 = gradient. 7 = y-intercept.
h) y + [tex]\frac{1}{2}[/tex]x = -4
Subtract [tex]\frac{1}{2}[/tex]x from each side.
y = -[tex]\frac{1}{2}[/tex]x - 4
One last thing. If you are presented with an equation without a y, the gradient is 'undefined'.
example : x = 4
This a vertical line passing through 4 on the x-axis. There is no 'b' because its not crossing the y-axis.
Why is it 'undefined' ?
As the line rises it, it does not 'run' left or right. [tex]\frac{rise}{0}[/tex] . Zero can never, ever be in the denominator. Denominators can't be zero. That is why we say it's 'undefined'.
Hope this helps.
