<span>tep 1 :</span>Equation of a Straight Line
<span> 1.1 </span> Solve <span> 6x+5y-4 </span> = 0
Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).
"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.
<span>In this formula :
</span><span>y </span>tells us how far up the line goes
<span>x </span>tells us how far along
<span>m </span>is the Slope or Gradient i.e. how steep the line is
<span>b </span>is the Y-intercept i.e. where the line crosses the Y axis
The X and Y intercepts and the Slope are called the<span> line properties.</span> We shall now graph the line <span> 6x+5y-4 = 0</span> and calculate its properties
Graph of a Straight Line :<span>
</span>Calculate the Y-Intercept :
Notice that when x = 0 the value of y is 4/5 so this line "cuts" the y axis at y= 0.80000
y-intercept = 4/5 = 0.80000 Calculate the X-Intercept :
When y = 0 the value of x is 2/3 Our line therefore "cuts" the x axis at x= 0.66667
x-intercept = 4/6 = 2/3 = 0.66667 Calculate the Slope :
Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 0.800 and for x=2.000, the value of y is -1.600. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of -1.600 - 0.800 = -2.400 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)
