Sunday, October 19, 2008

Finding the y-intercept using a point and slope

The y-intercept is simply the point where a line crosses the y-axis. You can find the y-intercept of the function f(x) simply by using 0 for x. In the line notation y = mx + b. The variable b is the y-intercept. If x equals zero, then y = m(0) + b which then will make y=b.
For most functions, finding the y-intercept, if it exists, is easy. You just plug zero into the equation. The answer is the y-intercept. But what if the slope of a line is given solely without the y-intercept such as : y=3x+b and a point on that is (2,5). Remember, a point on a line consists of an x coordinate and y coordinate (x,y). You want to replace the x and y variables in the equation with the x and y coordinate point given to you and solve for b.

5 comments:

Anonymous said...

sorry Mr. T i do not understand

Delroy said...

y=3x+b 5=3x2+b b=-1

Nathaniel said...
This comment has been removed by the author.
Anonymous said...

y=3x+b 5=3x2+b b=-1

Jason said...

y=3x+b 5=3x2+b b=-1