mkd009
Sep 7, 2009, 09:14 AM
what are the x and y intercepts of (-4,5) and (6,0)
what are the x and y intercepts of (3,7) and (-1,-5)
Unknown008
Sep 7, 2009, 09:24 AM
Work the equations of the line joining the points concerned.
To do that, find the gradient between the two points, and use the formula for getting the equation of that line;
Gradient = \frac{y_2 - y_1}{x_2-x_1}
\frac{y-y_{coordinate}}{x-x_{coordinate}}= Gradient
Then, put x = 0 to have the y intercept, and y=0 to have the x intercept.
I'll do the first one.
(-4, 5) and (6, 0)
Let (-4, 5) be (x1, y1) and (6, 0) be (x2, y2)
Gradient = \frac{y_2 - y_1}{x_2-x_1} = \frac{0 - 5}{6-(-4)} = \frac{-5}{10} = -\frac12
Now, the formula to have the equation;
here, you choose any of the two points;
\frac{y-y_{coordinate}}{x-x_{coordinate}}= Gradient
\frac{y-0}{x-6}= -\frac12
y= -\frac12 (x-6)
Now, I put x = 0 to have the y interept;
y= -\frac12 ((0)-6)
y= 3
Putting y=0,
(0)= -\frac12 (x-6)
0= (x-6)
x= 6
Now, try the second one.