This graph is y= 20x-40. Find the coordinates of the point where the graph crosses the y-axis and x-axis.
Answers
Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :
y-(20*x-40)=0
STEP
1
:
Equation of a Straight Line
1.1 Solve y-20x+40 = 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.
In this formula :
y tells us how far up the line goes
x tells us how far along
m is the Slope or Gradient i.e. how steep the line is
b is the Y-intercept i.e. where the line crosses the Y axis
The X and Y intercepts and the Slope are called the line properties. We shall now graph the line y-20x+40 = 0 and calculate its properties
Graph of a Straight Line :
Calculate the Y-Intercept :
Notice that when x = 0 the value of y is -40/1 so this line "cuts" the y axis at y=-40.00000
y-intercept = -40/1 = -40.00000
Calculate the X-Intercept :
When y = 0 the value of x is 2/1 Our line therefore "cuts" the x axis at x= 2.00000
x-intercept = 40/20 = 2
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 -40.000 and for x=2.000, the value of y is -0.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of -0.000 - (-40.000) = 40.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)
Slope = 40.000/2.000 = 20.000
